4000 hands is really a small sample. I know that sounds weird to say, but honestly it is.
Also, playing 25% of hands and getting to showdown 35% means you have been hitting the board well, or 2NL is just that passive. What I mean is you must be facing a lot of checking from opposing players to get to showdown that much, especially in limped pots.
Having such a gap between VPIP and PFR is fine for 2NL and 5NL, but beyond that it's a huge leak. Just beware when moving up, because raising and 3-betting is far more rampant at 10NL and beyond.
I've seen players with a VPIP of 15 who only go to showdown 28% of the time and absolutely crush 2NL long term.
Honestly, at 2NL, playing 15/12 and making an attempt to add more tables is the way to max your hourly rate.
It is very common to run for 10+ptBB/100 over 5K-10K hands and run break even the next 5K-10K.
Once you log 50K hands, things will become more clear in your statistics.