For continuous exposure (hours at a time) the danger level kicks in at 85dB for someone with normal hearing. That's not even restricted to UP hearing aids, most of your mild to moderate aids are going to output at that kind of volume cos otherwise you don't get any useful gain. The first bits of hearing that go are the frequencies above the speech area, so for me it's better to completely lose my 12kHz frequencies faster for a few more years of being able to make out what is happening at 1kHz since 1kHz is a whole lot more use.
For me, not so much an issue because I have a mixed loss, I've got 40dB of internal earplugs going on to protect my cochlears from loud sound, hence we can put on more gain than with a 100% SN loss.
I don't know what the specifics are with plan SN loss but it does seem to be that the danger area is hearing aids with a maximum output above 130dB, those with under 130dB MPOs provided they are fit correctly to someone who needs them they don't really cause any additional loss, no idea why and I can't find the research at this time of night. When you get to 130+ there are in-pack warnings that they might cause additional loss even when correctly fitted, but by that point is everyone interested in hanging onto an extra 5dB residual hearing or do they just crank up the gain? Is it worth preserving something for the future or more worth hearing now? Will the bit you lose be a bit you use anyway? Will it actually happen to you personally or will it always remain a mathematical and statistical risk that doesn't actually happen anyway?