Suzanne,
Please don't allow me to alarm you. I am going off my own experiences. It certainly is possible to have MDS and be iron deficient. Craving ice is common with iron deficiency. Other stranger cravings are common also. Talk about weird
With her being at a Center of Excellence, and the fact that the iron is helping, I would go for it. Keep asking questions, knowledge is power (I am quoting someone, but I forget who said it first, sorry). It sounds like her doctor has checked blood levels and has things under control.
Zoe