It kinda depends on the product, process, and equipment and what you are wanting to accomplish by doing the test. I would be much more cautious if I was producing refrigerated milk vs producing Capn Crunch.
To me it doesnt matter if you set the limit at 1, 10, 100, etc. If you have results of 2, 11, 101, it would be hard to justify that at these levels that the equipment is "unsafe", that the sanitation cycle was not effective, or that correcitve actions are needed. In most cases, the risk is not there. You are most likely "opperating" outside of sampling and testing error.
For this reason, in general, I'm not a big fan of developing "limits" for TPC for sanitation. I'd say go ahead and conduct them if you want. Establish a resonable baseline. Then track, trend, and investigate / develope corrective actions when if you see a trend up or spike. You could set up some measure such as above "X" standard deviation(s) where an investigation is warranted.