Maxed out Nerves only reduces KLs by 22.5%, Most receivers that amounts to around 1 KL per season. HIgh volume guy maybe 2 per season. Poss WR seems to be closer to half your KLs, but again, that might only be 3 KLs per season.
My low strength/carrying slot WR had 64 catches/12 drops last season without Poss WR, and 45 catches/5 drops with it this season. Might have got him 4 more grabs.