Not sure I understand, everybody's code I've seen always has something like this,

HSEROUT [B0, DEC 6] or how ever else you want to write it and the receiver is like this

HSERIN [B0var, DEC number]

I even saw one guy's command that looked like this:
HSEROUT [$FE,$47,0,2,"RPM = ", DEC5 RPM] (is sending to a serial lcd most likely but still)

and thus I was wondering why, in my case, does HSERIN need the commas to be transmitted (sorry if you've explained it, I just don't understand as I thought it was on the HSERIN side not the HSEROUT side)?