With the information provided, I don't think that you can draw any good conclusions. When myelocytes are high, it is a sign of marrow stress, but it is really difficult to ascribe a reason without more history and testing. Some causes are viral infections, vitamin deficiencies, hormone imbalances, and of course the other possibilities of some form of marrow failure.
The percentage does not seem that high at a glance, especially with everything else in order.
Unfortunately, I think that additional testing and patience are going to be needed to get to the root cause.
MDS RCMD w/grade 2-3 fibrosis. Allo-MUD Feb 26, 2014. Relapsed August 2014. Free and clear of MDS since November 2014 after treatment with Vidaza and Rituxan. Experiencing autoimmune attack on CNS thought to be GVHD, some gut, skin and ocular cGVHD. Neuropathy over 80% of body.