Please be very careful with MTBC. After well over two years, we were not aware that modifiers and units were not carrying over to them. A month ago, I had the V.P. of IT from MTBC come and meet me after a threating letter to their V.P. of operations. They claim they have been having this issue with A/C for about seven years. They way they told me send the modifiers and units in the "Account Information Tab" and input the information in the "billing notes". We lost a ton of revenue and they are in very thin ice with the providers. I hope this help.
Also, keep an eye on your aging reports. Anything past 60 days they tend to sleep on it. No follow-up.