Mrs. Mitchell, I'm not a doc, but know that even for docs there are no hard and fast rules for how to taper off Entocort. It's just guesswork. Your plan sounds fine.
As far as docs go, trust but verify.
AzJohnny, Entocort, taken for years, does pose potential problems: adrenal issues, rising blood sugar, vitamin D deficiency, and interference with calcium absorption. Also Entocort allows Crohn's to fester...causing slow damage, some of which might not be reversible. For instance, while on Entocort, my daughter's ability to absorb B12 has declined, and I'm not sure this ability will ever come back.