However, if the main college uses flat rate tuition for any number of credits for a “full time” student, then taking 12-13 instead of 15 credits in a semester is getting less for one’s tuition (and room and board etc.) money there, so having to catch up in the summer would be an extra cost (and less or lack of work earnings) beyond the originally budgeted 8 semesters that would still cost the same.
I.e. if the student is likely to take more than 8 semesters (including additional summer sessions), be sure that the college budget allows for that.