Would I be summarising correctly if I said that "perception of impermanence" is perception of the subjective experience of impermanence, as distinct to perception of an objective reality of impermanence?
I would like to skip the "subjective" and rephrase "'perception of impermanence' is the result of the interactive play of the aggregates".
But thanks for the question ...
... it now dawns to me that maybe the discrepancy you seem to be seeing between your wording and Tilt's is that you are referring to impermanence qua characteristic of sense objects
and are assuming that Tilt is referring to impermanence qua impermanence
("impermanence as such").
My basic assumption always has been that the talk about "impermanence" is the talk about "impermanence qua characteristic of sense objects" therefore I could not detect a difference in meaning between your wording and Tilt's wording. But maybe I simply do not know the views of both of you (?).
But actually whether the former or the later conceptual aspect of "impermanence" is referred to doesn't make a difference from my perspective.
Because I think there is a 2-step synthesis (conceptual fabrication) involved:
1. fabricating the impermanence of a sense object (impermanence qua characteristic of sense objects
2. fabricating impermanence qua impermanence
If there is step 1 there arises instantaneously step 2.
Why is this?
Inference of an alleged characteristic necessitates its identification and "identification" always is a conceptual "isolation", a determination ("this is that"), a manifestation of consciousness (which is rooted in ignorance).