I think that's because client CMS is blocked by client. Try to set filtercmdstuff to 0. But I think using this way is not good , it's like using no recoil script.
See amxx server side aimbots or no recoil, no spread , something like this :
https://forums.alliedmods.net/archiv...p/t-81644.html
and look how they changed recoil.
P.S. If you want to use client cmd method then use eng_clientcmd to force attack and if you want to make it more accurate then make "wait" to be done by plugin not by client.