What do AHRS, EHRS, QHRS mean on a transcript? What do the abbreviations AHRS, EHRS, and QHRS mean on a transcript?

My guess would be:


AHRS = "all hours"
EHRS = "earned hours"
QHRS = "quality(?) hours"


What are the differences between these things?
Attempted Hours  
Earned Hours 
Quality Hours


Source