Sometimes there may be inaccuracies in such calculations. FPS rates determine frames produces per second, and this really isn’t too important in slow paced games, the fps will always be low when objects aren’t in a stationary form.
When I measured the FPS on my test project no action was present, thus nothing could interrupt such calculations delaying the ongoing increase of the FPS. Even in my complicated project, when FPS was measured I noticed it was around 60, but the still was stationary.
Your two projects have action, and in the process of an active trail art it is commonly likely for FPS to drop as drawing trails involves producing images. Same as your other project which had constant movement meaning that the FPS never really had time to settle.
Do not get too concerned, if it were below 10 then I would be concerned, but around 35 means that there is ongoing action which causes slight delays in the calculation of FPS. Your projects are fine, as movement is smooth and consist of no evident bug in my approach of it.
Also, by looking at your code I noticed that self wasnt contained in the project. The files are old and the back scene would have many clogged up JSON keys causing a slow, FPS rate. If you were to update to self, then leave these on your drafts, a spyglass would appear telling you to wait as the project is self-removing these unnecessary clogged JSON keys.