How many layers of felt paper can one put down to level out a floor?

I have put down a patchwork of plywood of various thicknesses (1/2, 3/8 and 1/4") to flatten out the floor and am now in the process of "feathering" everything out with paper.

To bridge the difference between one thickness and the other I have to start with many layers of paper.

How many are too many?

Does it not get to a point where the floor will be sort of springy?

Thanks.

one layer, per standards.

It depends on how much you are building up. I carry 30 lb felt for that and on occasion use 90lb roll roofing or standard 3 tab roofing shingles.

Thanks!

Have yet to read that standard.

It is common practice and even taught in the NWFA & NOFMA schools, to build layers as needed, to an extent.