Has anyone done 2 courses of letrozole in one cycle?

My RE had me take 5 mg letrozole cycle days 6-10. I went in this morning (cycle day 13) for labs and an ultrasound. The ultrasound showed 4 follicles, but only about 9mm each. They just called about my labwork, and now want me to take 7.5 mg letrozole for 5 more days and come back. Has anyone else had a similar experience?