Question

Trane Model TUX120R960V2 - The igniter recently failed on this unit and I had a repairman in to replace it. He informed me at the time that the unit had a 90 Volt igniter but he was getting a reading of 120 volts on the line coming into the igniter. He had a 120 volt igniter in his truck so was able to install it in place of the 90 volt to get heat back into the house. He then informed me that the circuit board contained a chip on the board that reduced the current going into the igniter down to 90 volts and that ultimately I would need to replace the circuit board ($650) and put in a 90 volt igniter ($120+). In addition to one other part which I can't remember what it was, but the overall cost will approach $1,000. However, the HVAC is working just fine with the 120 volt igniter in place. I don't see a need to replace all these parts for the sake of having a 90 volt igniter verses a 120 volt one. Can't I just carry on with the 120 volt igniter in place. Please advise