I have a friend who recently purchased a B7300 (pics attached) with a newly installed mower deck. With the deck installed and working properly, the arms on the 3 point hitch are limited in their lift height. (2) brackets that came with the mower deck have "ears" that prevent liting the 3PH very high. Do these brackets (pictured) need to be removed with the mower deck off to fully realize the lift height on the 3PH? The ideal situation would be to remove the deck only and NOT remove the brackets and hardware to be able to use the 3PH.
The MMM mounting system seems very similar to the one I have on my Kubota B7100. On mine the two brackets are slightly different. When the mower is mounted the three point lift height is set by bottoming out on the mower subframe and having the lift lever adjust set to coincide with this.
When the mower is removed mine has adequate lift height.
Perhaps look into the adjustable rods to the mower lift and where the lever disconnect is set. Changing these might make a difference. Be carefully and ensure that the three point lever control cut out is not set too high?