Like OT and PT, PR is billed in 15 min units. More than 8 min and you bill the next highest number of units. If more than 1 CPT/HCPCS is billed during a calendar day, the total min is constrained by the total treatment time. My question is does this applies to all modalities. For example, do all the minutes for the following codes have to be lumped together for a single day if they are all performed at the same session: G0237, 97535, 97750? Also should group code min and one-on-one contact min be lumped together for billing?