Interesting
It is either a typo or maybe the 3.15º is laid from the LOM at 2300 to the threshold plus 50 ft, so that overhead the VOR the altitude should be 1600, which is 100 ft higher than MDA.
This would mean that in marginal weather it would "pay" to fly this approach dive and drive, as this would enhance the chances of becoming visual in 100 ft (600 m less of visibility that you need).
I think it is a typo