The suggestion is dont waste the money because it will do nothing for you.
The PSU IS the voltage regulator for the miner. That is why they have a variable input range but always output a stable voltage. Whether you feed a PSU 210v or 240v, the DC output will still be the same.
You should double and triple check what you hear, especially on the internet, because whoever told you that is pretty clueless.
What kills ASICs is poor environmental management 99 times out of 100
I think the OP's question is valid. The topic interested me after hearing possible problems with the S15 power supplies requiring stable 220 voltage. I keep checking for that vary reason after Phil started looking into:
@ yankees.
I purchased this item in theory it will put out 220v +/- 5% so 209-231
https://www.amazon.com/gp/product/B071V5NXZV/My input is 243.1 and my output is 220.7 on my hand held meter
the meter on the unit read 243 in and 220 out.
If the new units need to run @ 220 I would need more info before purchasing a 7nm Antminer with my input of 248-252v