Ed,
That is correct but there are several variables involved. First of all, the difference is very slight....on a 350 small block, the difference in compression from std bore to .060" oversize will be about two tenths of a point. In otherwords if your compression was 10 to 1 with the standard bore piston, and you went to a .060" oversize piston that was exactly the same as your std piston, then the compression would be about 10.2 to 1 ... not a big difference. The only thing is ... most manufacturers "adjust" thier oversize pistons to keep the compression ratio the same. Sometimes they will move the pin hgt slightly, or change the dish etc. I am talking about stock type pistons here, cast replacements etc, not the good performance pistons.
So basically, your guy is correct, but the difference is not enough that you will ever notice it.
