Why plywood gets its own feed rate
Plywood is not a uniform material the way solid wood is. Alternating veneer layers bonded with glue lines mean the cutter is constantly transitioning between wood fibers running in different directions and the glue itself, which is harder and more abrasive than the wood on either side. A feed rate tuned for solid wood tends to push too aggressively through those glue lines, causing tearout, burning, or premature tool wear.
How the number is calculated
Feed rate equals spindle RPM multiplied by the number of flutes, multiplied by plywood's default chip load, which is set lower than solid wood specifically to account for the glue lines and cross-grain veneer layers plywood is built from.
Practical tips
A sharp, high-quality bit matters more on plywood than on solid wood, since a dull edge tends to chip the face veneer rather than shear through it cleanly, leaving visible splintering on the top surface. Climb cutting on the final pass, or scoring the top layer with a shallow first pass before the full-depth cut, both help reduce veneer tearout on plywood parts that need a clean finished edge.