yeah this is pretty standard,

I understand you querying it though, 99/TT even JJ a pain in the arse hands quite often, they are easy over value when they flop as over pairs, and they dont often flop as over pairs anyway.

I don't like 3betting TT it gets you in the shit, you're weak against the continuing range and you don't exactly hit a lot of flops that you can bet out on with good outs, as aposed to hands like Axs or sc's in pos that can continue on more flops and are easy to get away from on missed flops because your never 3bet pre with any notion of value, its all in the implied odds