The reason is ASR router is a hardware switching based platform compared to other routers
like 7200,7300, 3800 etc..which are software switching based platforms.
For hardware switched packets, ACL counters will not report any value. If we need to see the matches or
the actual packet details, you may want to put in a 'log' keyword and force the packets to hit the CPU.
we have to be careful if we have huge subnets permitted or denied in the ACL.
HTH,
Mani