Is grading becoming too subjective?

A few months back, I cracked a 1909-D Gold Indian Head graded MS61 by NGC out of its havily scuffed and scratched holder to make up a 5 coin minimum submission. This coin came back from NGC in bodybag. The same company who previously graded the coin MS61 said the coin was "improperly cleaned".

Last month, I sent the coin to PCGS for a free grading (their quarterly members special) and it came back AU55.

Makes me wonder really how one grader sees it as "improperly cleaned" and other as "about uncirculated". Coin grading is not a science but I guess a bit of consistentcy among the top TPG's is too much to expect.

Cheers!