Id be checking if the referring diagnosis is correct. Even if it is, now is a chance to submit a request for a Independent medical review, and ALSO a rebuttal letter. I didnt feel good about them sending my package up with the sole diagnosis of "lumbago", so i opt'd for a IMR and pleaded my case as to why lumbago should be two diagnosis (spondylosis and sciatica), in my case it worked out in my favor.
The 618 is pretty much what your local board wants to send you up as to afpc, but this time also gives you a option to speak your situation. Dont sign a dang thing until you read the AFI on how this goes down. Many peblos are trash and will try to hurry you through since their case load is more than they can handle (and should be per afi).
AFI 41-210 para 4.65 outlines what should happen, dont let them trick you or give you a sob story on how much they need to get done. I was lied to by 3 contracted peblos that would have tanked my chance at a fair rating. Worst comes to worse, have them run your questions by the SGH (typically the MEB board president), they run the meb program for the MDG CC.
Reference the Medical Standards Directory for the criteria as to whether your conditions should be included in your MEB and forwarded to the PEB. Otherwise, the above post by @Noobzor was a good statement of the issues to consider.