Activity 2(A) Moving between seated positions

So my client with the lumbar spine problem cannot transfer from one seated position to another seated position located next to one another without standing up and sitting back down (but to be clear he can stand up, brace himself and sit in another chair next to the first).  The WCA Manual suggests that this descriptor is meant to address wheelchair users that cannot move into and out of their wheelchairs without assistance.  However, the way it is worded does not limit the activity to wheelchair users.

I am pretty sure my client will be assessed with Activity 2(B), but wanted to ask whether it was worth pushing for 2(A) on the basis that he cannot, strictly speaking, move from one seated position and another seated position located next to one another.  Is their case law on the above?

I don’t interpret the transfer as having to be completed in any particular manner, so standing fully is still performing it. The only argument might be if the claimant is taking a significantly longer time to reach the second seat than a person without the disability would - I know this isn’t PIP, but I think a similar concept can be implied into the WCA.