No. If your reagent is old, it’s going to be less effective, not more. Having said that, if you have been using it for two years, probably should order a fresh one.I checked my Fas-Dpd reagent, it has a best by date of 2019. I bought it in 2019. When these reagents get old, do they over-report FC like that? If so, that pisses me off.
During SLAM, you should be testing FC multiple times daily. I would shoot for at least 4 times, so you can get your FC back up to SLAM level.
After SLAM, you can definitely keep your FC higher rather than lower. Shoot for a couple of points higher than target level. That’s not minimum, by the way.
And test a few times a week, if not daily, until you have a firm handle on your pool. Most of us get to the point where we can guess what our FC is, even before testing, and come pretty darn close.