Your platelets of 200 something look fine to me. Dropping 40 thousand might be significant (might not be, though). It might be the same value 3 months from now, could go up, could go down.
I don't know what the MVP means. If I were you, I don't think I'd worry too much about what it means (in the grand scheme of things.) Sure, it's good to know what your lab values are, but when you start trying to figure out what the MVP and the CPK and MCV and the RMV and the RAC and the PT and the PTT and the INR and the .... :) (the list goes on), you'll run yourself nuts! :) And then, by the time you think you have it all figured out after you've run yourself nuts, your labs will all change again.
I think your platelets look good. :)
See:http://encyclopedia.thefreedictionary.com/Mean+platelet+volume
"Mean Platelet Volume (MPV) is a measurement of the average size of platelets found in blood and is typically included in blood tests. Since the average platelet size is larger when the body is producing increased numbers of platelets, MPV test results can be used to make inferences about platelet production in bone marrow."
Mike