There have been many discussions about productivity expectations in the forum if you do a search. There are so many variables. To me, 120 per day sounds high. However, in my organization we work with SEVERAL different EHRs and computer systems. In some organizations, you have a worklist with all the information - just one click. We are also coding for CPT, ICD10 and modifiers. In some you may only be coding CPT or only ICD10. Or you may work only in radiology, coding CXR for 40 of those 120. Or you may only spend part of your day actually coding.
For my team, I expect my coders to code office services (E&M including procedures/labs) at about 10-12 charts per hour. Inpatient, about 5-6 per hour. However, they also have other work and even if coding office services that day, I would not expect 80-96 in a day.
If your organization expects 120/day by 6 months, I would evaluate the productivity at 3-4 months, and then see how much speed improvement is needed.