It is a sad fact of life with the I.o.M issues that for years dealers buy-in prices , of mint stamps ex collections for postage use , are a tiny fraction of face value (15%) . Even much lower than they offer on mint GB (50-60%). Some bulk mailers have been posting in the past from I.o.M to take advantage of low postage costs but fewer do so recently due to the extra work getting material on to the island as the stamps need to be cancelled there , not valid for mail originating in mainland UK . With a load of unused GB collections available, discount postage using GB stamps from 1980- 2000 is the easier more convenient option for dealers catalogues mailing.
It is not surprising Scott has dropped the pricing as a reflection of the market. I suspect there may be more to come.
what ever it is , it's better than a poke in the eye from a wet umbrella!