I purchased a router table mounting plate to go inside a custom made table. The insert includes some crown in the middle of the plate. The height of the crown is roughly 0.030".
At fist I thought this was a mistake, but after reading the back of the package it says this is by design and that it insures the work is at the highest point. The consensus here http://lumberjocks.com/topics/39338 seems to be that the reason for the crown is so that when the router is mounted on the plate, it sits flat.
The primary use of the table would be for joinery. I am a novice woodworker, but it seems that the crown imparted would do more harm than good in this scenario. I have 3/8" aluminum plate on hand and am considering using that to build the insert.
Will having the crown on the pre-made plate be better for my purposes than the flat custom plate?