19 cm is only 7.5 inches. that is NOT long enough to properly tighten pedals, and it's pretty much impossible to overtighten them. I would want to see you using at least a 30 cm wrench/lever, so that you can get adequate tightening with only about 30 lbs of pressure on the wrench (pedal wrenches are typically about 30 cm long) . Either get something you can use to add leverage to that wrench or get it tightened down properly with a pedal wrench before any more riding is done. As for progression, that is a small effect over time, not enough to offset inadequate tightening.