not 100% sure what you mean.. do you mean VPIP/PFR are close together? or differences between nit/TAG and LAG are small?
i think it might be because they are just ballpark figures/estimates. i'd consider a 18/18 a pretty tight TAG, or 20/18 for example. but also 25/20 could also be TAG but on the slightly laggy side. its just how i see the numbers/categorise the players and everyone will see it slightly differently i guess.
the larger the gap between the VPIP/PFR then obviously the wider they are coldcalling (with respect to overall VPIP). depending on how the limit plays, if you have a wide coldcalling range you may be opening urself up to getting squeezed, maybe you are leaking money postflop, or you might be missing out on some spots to turn some of those worse hands into 3bet bluffs for example. hard to say tho.
about 3bets, its really limit-dependent i think because you could probably get away with 3betting a completely merged range on nl2/nl5 for example and that might have an effect on the overall frequency of 3betting. but if you have a solid 3betting game i guess it could be anything between 8%-12% depending on things like postflop edge. however i havent seen many people on nl25 or below with much more than 10% and most regs seem between 6% and 10%.
you are definitely wrong to treat 23/21 as lags! maybe it will help to look into opening ranges for your own game and then once you get a feel for what is good you can compare to others. generally from EP-SB some good open raise frequencies are: ~12%, 16%, 26%, 55%, 35%. if you are just coming from fullring it makes a lot of sense to play tighter just to get used to the dynamics, but if you are playing tighter than this you will definitely want to open up more sooner or later. as you improve and get more confident you can open up more than this too.
