What is the difference between dropping a course and withdrawing from a course?
Students are allowed to "drop" courses during the drop-add period. Students are not charged for courses dropped during this period and the courses are not counted toward the student's completion rate. If a student "Withdraws" from a course after the drop add period has ended, the student is still charged for the course and the course does count toward the student's completion rate.

There's a class starting later in the term that I would like to take. Why can't I receive financial aid for the course if I add it after the standard drop-add period?
The college must establish a time and date used to determine the number of registered credits on which financial aid is based. The date LSC uses is 12:01 a.m. the day following the term's drop-add period. Only the credits for which the student is enrolled at that time are counted when determining financial aid eligibility. Had you added the late starting class before the end of the term's standard drop-add period, it would have been counted in the financial aid calculation even if it actually starts later in the term.