Paperstars, excellent questions and good use of your analytical suspect re: differing interpretations of astral and lucid states.
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Ok follow along if you will: It is time to read.

Perhaps too often people jump on the wrong freight train when thinking outside the box on the subject of astral projection.
Bare in mind, this is my opinion to this in-depth subject, it does hit home with me.
Outside of any logical induced approach to that of astral, there will always be the question of Astral or lucid dreaming as a question in peoples mind.
You will not find many which have undergone the clinical approach to astral projection.
In this particular research format, it establishes routines that allow for some idealistic conditions for the practitioner. Conditions that are tended to by a staff of many others that monitor and maintain a controled environment best suited to trial and error and succes.
Conditions which are not always present on personalized basis within daily life.
At the same time, there are many others which are behind the scenes that gather a ton of data stemming from biological/physiological and psychological analysis data of the participating person(s) that are engaged in the application of induced astral projection.
Because there are so few (which will speak of this research in controlled studies) that is tagged to the studies of astral projection by induced methods, all else would be what is called "random events."
Beyond the given control charts of random activity associated within the parameters of astral projection.. the field of true hits tends to dwindle very rapidly and become categorized as lucid effect dreaming.
To the lucid dreamer, it appears quite realistic.
There may be threads of actuality associated with lucid dreaming which can raise the flag of suspect potential for experiencing astral projecting or even getting fragments of futuristic events that come as result of suspect time/continum and peeking beyond the veil, so to speak.
What differs from suspect and actuality?
A random event and induced (self induced mostly - result of perfected auto suggestion or hypnosis) are two different animals.
One is a natural event that stems at will few and far between as a result of natural nocturnal (or sleep) states for what takes place. While induced, is the willful command over the subconscious to enter an altered state with a specified objective or agenda precalculated and preplanned.
What remains, is that of the data recall from the event and validation.
Those in an altered astral state can usually thrive upon multiple thresholds of consciousness which allows the conscious, subconscious and super-conscious to determine a specified pathway leading to that pre-calculated objective. Without an objective it is mere recreational soul flight for passing into an ethereal state and penetrating the veil of one plane to that of another (which tends to be confusing to some).
Those that reach these levels by self induced, are much attuned to metaphysical principals that all things vibrate complete and house no limits or barriers, where energy and mass becomes simply parts of universal laws that can be blended and passed without restraints as long as you follow the rules and alter to that of a compatible state.
Among the greatest road blocks in these arenas of astral projection, are the mind sets that become conditioned from birth forward, about limitations and that of perception, and fear.
Within the confines of the physical consciousness (for most) these limits are stamped as tangibles.
Within a complete altered state, this slate is thus clean and free of those principals of conscious limitations. It is a huge transition to redefine the thought process for what is instilled in our daily lives, perhaps as why there are so few that continue the practice and will speak to it.
By the way... I like your theory of the book and the page number.

In practice this would be noted as a Target.
Another method for creating targets, comes from what we call Beacons. Beacons are most often objects that hold a familiar energy that has been personally charged (such as a crystal or animate object).
The object then becomes placed somewhere by another person... the objective is to create a paranormal scavenger hunt and find the beacons.. return to the physical, log it to the research journal and compare the end results for accuracy. These things often lead to something much bigger in the picture of externalizing and escape of the physical realm. These things are often pre-curser to investigative work, cold case work, search and rescue and the list goes on and on (on the forefront of positive application).
Well and good perhaps; but, somewhere like night and day or positive and negative, there is a darker side that some have gravitated towards.
There are others that may twist things a bit and utilize matters for less than positive application, but I won’t go into that here.
One thing I feel is important to note:
As with many of the gifted facets, there is a tremendous alliance with humble humility that accompanies the gifts. There are certain thresholds that need respect. Less than understanding these thresholds, it places an "at risk" for many undesirable effects and side effects.
• I worry about recreational approaches to some of the more stringent disciplines of paranormal practice. Perhaps because of the potential physical and psychological impacts more than the effects of overreaction to suspect dangers that have not been reconciled between a physical state and a pseudo spiritual state of mind impact.
Random on the other hand, seems a natural thing for most people.
The greatest concern ( in my thinking) would be; how big of a sore spot on your head (or anyone else’s head) would there be, from scratching it and wondering what the heck took place, and what it all means?