You are right on both counts.
1. Classic poker rules that noobs screw up.
2. Overchip applies to only 1 chip. Thats the reason it is there. When you reach for two overchips, that is a raise, and yes it counts.
If the future verbalize your bets

. Tell your buddies they have to wear their underwear on the outside of his pants for the rest of the tourney for challenging the TD and being wrong.
Good thing your the TD.