W$SD% decline causes/cure?

In the last 3 months I've started playing a 21/18 style that has been fairly successful (6bb/100 at 25nl 6max). My concern, is that my W$SD% has dropped from 51 to 47. Can I continue to win with a rate this low?

What can I do to improve this? I thought I might be calling down too much but my river call efficiency is 1.86. I think a big chunk of my losing showdowns are check down pots (I won't fight for small pots out of position with air) and also, after a c-bet/call and check/check on the turn, I rarely fire on the river without good reason.

Another concern is that my WTSD% has crept up to 26%. I'm sure this and the W$SD% are somehow related.

Hands bb/100 VPIP% PFR% 3Bet% WTSD% W$SD% Agg Agg% W$WSF Steal Pct Flop CBet% Turn CBet% River Call Efficiency
64301 6.02 21.2 18.3 6.5 25.9 47.1 3.71 37.7 47.9 33.7 81.9 43.6 1.86

Any advice is appreciated.

What were your stats before changing to 21/18? What's the sample size for 3 months of play?

Is your non-sd winnings line going up while your W$SD is going down?

If you're seeing more sd's (i.e., WTSD is going up), there's a good chance your W$SD will go down if you're not specifically picking spots to increase your WTSD. Could also be simple variance.

Your value betting on the river probably needs some work (this is a very common leak). When you say you won't fire the river without a good reason on cbet/call, check/check, what's a good reason? cbet/call, check/check is usually a draw or a smaller pair looking for a cheap sd, so our river betting reasoning should take that into account.

I was playing a much tighter 18/15 game. Sample size is about 150k hands.

Non-sd winnings have definitely gone up, while W$SD has gone down. It used to be negative non-sd winnings and they are now flat to positive. Sd winnings line has flattened but still positive.

Overall it's been a significant change in my playing style. I like it and am happy with the results. My concern came after comparing with the HEM suggested stat range for W$SD. Shows that median bb/100 for 48-50% is 1.66 and <48 it's -4.12.

fwiw, I'm going through the same thing right now, switching from a tight TAG style (bordering on NIT) to a looser TAG style (around 20/17), and increasing my AF and Agg %, and seeing the same pattern. I'm much happier w my game, even though my blue line isn't as terrific as it used to be... but my red line is flat now, which it never was for me before. Net result is that my winrate is going up, and that's the line that counts...