Questions About Score and Mines

1: Just had a game on Remagen as an engie where I had 498 combat score at the end, 600 attack, 400 defence etc. But my engie only leveled up 20 points? Is that a server side thing or a punishment thing? No tks, but I switched squads 3 times because sls left and the server had a punishment mechanic. Had like 30 kills, 14 deaths, 1 recon tank destroyed, 1 truck and I barely got any leveling on my level 2 engie.

2: What is the place cap for mines? Do they respawn after ~4 or so places by an individual?