The way I understand it is the following:

Only after 10 mg do you need to slow down the pace of prednisone tapering. A prednisone dose of 7 mg is roughly equivalent to the average amount of cortisol the adrenals should produce daily. Keep in mind that the adrenals should be capable of producing 10 times that amount of cortisol during stressful situations. Stress seems to be the trigger that causes people to have flares. Cortisol is the "stress hormone" so a cortisol shortfall during times of stress tends to create problems.

When someone is stressed their cortisol need increases. If the adrenals don't pick up the slack, more prednisone may be needed. During severe stress, people are at risk of an adrenal crisis if they have adrenal insufficiency and don't receive steroid replacement therapy.

All this assumes the underlying disease activity is no longer active and people are able to taper down to 7 mg. After 7 mg people should go slow but there is no universal tapering plan that will work for everyone. The length of time people are treated with prednisone largely dictates the rate of adrenal recovery.

I was unable to get anywhere near 10 mg for ten years after PMR was diagnosed. There were other factors so not just PMR that prevented me from tapering lower than 10 mg.

What worked for me after Actemra was started was to stay on 3 mg of prednisone "for as long as it took" for my cortisol level to improve. After my cortisol level improved, my endocrinologist said tapering from 3 mg to zero was no longer needed. I tapered anyway but it only took me a couple of weeks to taper from 3 mg to zero. About 8 months was the period of time I stayed on 3 mg of prednisone. while Actemra prevented a PMR flare.