You cannot chose here between the codes. If the visit is for the injection then you must code the injection code you cannot elect to code an office visit because it pays more. If the visit is to evaluate an ill individual and in the course of the evaluation then an injection is administered you may bill the office visit with a 25 modifier and the 96372 with no modifier.
Every procedure including the 96372 has as an inherent part of the procedure the assessment of the patient necessary to complete the procedure. However when documentation supports that the assessment was over above and beyond the procedure then you may bill for both. The reason for past denial may have to do with "trending", payers perform post audits and then based future pay decisions on the results. Post audit has demonstrated an abuse of the 25 modifier, in that documentation does not support its use most of the time. Therefore they pay one or the other, office visit or procedure and sit back and see what your response is. If you do not appeal then you have confirm their suspicion.