I too had similar experience on MR issues with DT and some others as well .they seem to be insist on their own releases to be used. (to my experience this has been  the case pretty much for  all other micros but I don't see why they don't  just create a generic model release that could be used on all of them.they are well aware we are uploading multiple sites and it is just nothing but inconvenience to expect us to get 6-10 different releases signed by our models.(too much unnecessary paper work)
now I am using a generic release for all sites it seems to be doing fine  but I don't know if it might be rejected at some point or not. I think they should notice that it also looses them time and money as approval of images delayed and same files need  to be reviewed all over again 
I do understand why they are being so strict on MRs but since there is an easy solution why let this problem keep going.?