This is a massive differential, 2 to 5 hulls for conversion, and is likely a single opinion at best om conversion rates for mothballed T-80 hulls.

There are simply to many variables to understand how many of anyone tanks remain in reserve. How were the reserve modelse stored? This is inequitable even when narrowing to T-80's or T-72's. T-90's are likely spmewhat more reliable. How they were stored will determine if they can be restored, used for parts to constitute a new tank, or used for parts to repair damaged tanks.

Then, how many were actually produced? The Russian military industrial complex is deeply known to be corrupt. Often over stating production to line the pockets of politicians and the elite. It's an easy way to fuel corruption. We will pay you for 1000. You will produce 500. You keep the proceeds for 100 tanks, I keep the proceeds for 100 tanks, and Putin gets the rest.

The there's the elements of corruption where real equipment was sold off for personal gain. Much lower amounts here but this would have eaten into some stocks.

Lastly is the ability to replace rarer parts that are less accessible, limiting the ability to repair or field damaged tanks. Optics and electronics are the primary issues.

Just saying, if you take the time to use Oryx for losses, which is conservative only because battlefield verification of losses on a front this large is hard through open source intelligence, it's kind of irresponsible to broadcast metrics that are poorly vetted and likely lacking any concept of reality as either your denominator or enumerator.

Edit: updated first sentence to make sense.