Increasing a stat decreases the others, so you have to increase them back if you want to keep them balanced.
Each time you level up, you get a few points to spend in five stats of your choice. Increasing the first one, power, will reduce the other four a little. They are related to the precision of your shots and can even go negative. Increasing power is presented as the long term goal, but you cannot leave the other stats untouched if you want to keep them at the level you want.
Upgrading power creates un unbalance that you then seek to re-balance. That system is comparable to the game loop of balance -> upgrade -> unbalance -> re-balance often found in management games where improving any part of the system creates unbalance (building a new industrial zone in sim-city means you’ll have to re-balance residential and commercial zones).