Fill Volume PQ Dillema for Lyo and Diluted products

I have a question in regards to injectable fill volume PQs.

My question could best be understood stating my probem by using an example.

when we quailfy a single dose injectable with a label claim of 2mL. Th formualtion department suggests a fill volume of 2.5mL with a tolerance of +/- 0.2mL. In order to ensure that our IPC checks are adequate we valdiate the filling system to ensure that the results are reliable. This is done by ensuring that the majority of fill results are within the tolerance limits, and allowing for some to be overfilled to a hard upper limit (an agreed value by the RA,QA and operations departments). The hard lower limit would be the label claim plus USP guidelines with respect to deliverable volumes. During a validation run nothing can go above or below the hard upper and lower limits and only a certain percntage can go in between the hard limits and the tolerence limits.

Therefore if we were to overfill or underfill within those hard limits there would be no impact to the consumer since this single dose shall be measured out via a graduated syringe to the recommended dose of 2mL. Therefore the concentration deliverd should not be a concern to the patient.

However the dilema is as follows:

For product that either requires roconstitution (lyo) or dilution in the acutal vial where the drug was filled…can I fill outside the limits suggesed by the Formulation depratment?

I don’t think so since we would be altering the patients dose concentration. Is this the accepted pratice in industry with regards to this?