It only takes $4000 of tuition and other qualified expenses to get the full $2500 American Opportunity Credit (AOC). And you have 2 students, the max is $5000 for $8000 of expenses.
The fact that you only got $2375 last year says you are lower than average on expenses. Compare this year's form 8863 to last year's.
If your students are on scholarship (box 5 of the 1098-T), there may be a loop hole that allows you to still claim a full tax credit. For more help, provide more info, particularly what's on the 1098-Ts
