ESA and DLA contradictory results

My husband was placed in the work related activity group for ESA even though he cannot leave the house due to his condition except to attend hospital,can hardly do anything for himself, can't walk etc. I thought this was a mistake by the dept but was told we had to appeal. In the meantime he has now been granted DLA at higher rate both care and mobility which is fantastic, so why should we still need to appeal on the ESA issue - surely the fact that he has been awarded the DLA at the level he has should speak for itself? He is on contribution based ESA so obviously with the recent change it's important he is placed in the support group to ensure his ESA doesn't finish after a year.

It may not speak for itself, because the distances for how far you're expected to be able to walk are different - 30m for ESA but further for DLA.

Here are the relevant support group descriptors

"Walking or moving on level ground
Cannot—
(a) walk (with a walking stick or other aid if such aid is normally used);
(b) move (with the aid of crutches if crutches are normally used); or
(c) manually propel the claimant’s wheelchair;
more than 30 metres without repeatedly stopping, experiencing
breathlessness or severe discomfort.
2. Rising from sitting and transferring from one seated position to another
Cannot complete both of the following:
(a) rise to standing from sitting in an upright chair without receiving physical
assistance from another person; and
(b) move between one seated position and another seated position located
next to one another without receiving physical assistance from someone
else"

Thankyou for the helpful replies and clarification. I did lodge an appeal as soon as they told me (even though I just thought at the time they had actually made a mistake!)so will prepare beforehand.