for pinnacle at max. they only provide 1.5% (if redeemed 1rp = 1rs.), and none of wallets that I know charge <2.3%, which is straightaway loss of -0.8% itself (again, consodering reward points as 1rp = 1rs. which is rare case).
//could you share where you're loading because without benefit its pointless to think about 20% limit when net is negative.
anyway, no such restriction. Only restriction, you can earn only upto assigned limit in that statement means if you prepay and spend again doesn't give any points.