You jumped through a lot of assumptions really quickly there to arrive at a conclusion.
Let’s just test the facts;
You didn’t list which quarq you have, but most are accurate to 1.5%. So right off the bat you are right on the edge of the margin of error for the device itself.
You also must be a monster, because if reducing a 2% margin gets you 15w, you’re sitting with a 750w FTP. What you likely meant was your FTP was 325 and that means 6.5w…again, assuming margin of error.
Your final comment is the most important, and I can’t find the discussion that took place on it here, may have been on the FB forum before this site properly launched. There was a study that had the distribution of L/R, long story short 1) there was nothing conclusive showing 50/50 was optimal, and 2) most people fell within a +10/-10 distribution and that was entirely “normal”.
You can work on an imbalance if you think you have it. Single leg drills both in the gym and on the bike. Though 52/48 I would not classify as an “imbalance” by any stretch.