PIO change on ATTiny85

Hello all.
My first post ever. OK where to start. I have here 750 PCB’s I had manufactured. The board works really well except for single ATTiny85 I have designed into the circuit. All it dose is watch the temperature of a high power MOSFET on the board and controls a fan to cool that FET. The problem is I have utilized PB5 on the ATTiny85 at my ADC input and PB3 as my PWM output. I am using an Arduino editor and a Arduino UNO to program the ATTiny85. This setup also works well programming the ATTiny85.
The problem I am having is, in text that I have read, “before any testing, If I only knew,” it states that if I disable the reset fuse which is the primary function of the PB5 it will allow me to utilize the other functions of that pin. Well that didn’t work. At least not as simply as my program is written. I can get the program to work on other pins just fine but not the reset.
I am very much a newbee to micro controllers in that I need to learn now how to manipulate different registers. Seems a bit over whelming. I would really appreciate any assistance any of you may offer. I am including a copy of the program. The only alternative is to discard the 750 boards I already have and order new ones. I would really rather not for financial reasons. Thank you

Analog_In_PWM_Out-D.ino (573 Bytes)

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That is correct. But PB5 is my ADC input PB3 is my PWM out. I did like the link. Thank you.

Which core are you using?

Some don't properly support the case where rstdsbl is set.

Mine does - and I would expect that code to work with my core.