[Avodah] why stop learning?

[David Riceman]

RSZ:

<<isn't this just a business deal, buying schar with money.....?>>

RTK:

<<The G'ra declares his willingness to give up his schar and Hashem 
either does or does not transfer the G'ra's merit to the lulav-owner's 
Heavenly bank account.
<snip>

In the case of learning in the zechus of a person who [A] needs a  refuah
sheleimah or [B] has gone on to the next world, it may similarly be the  case
that I express my wish and intention that my learning go to purpose A or B,
  and Hashem either does or doesn't apply the "deposit" of my learning to
the  account of the person I wished to benefit

 >>

Perhaps I spent too much time learning Moreh Nevuhim when I was young, 
but this makes no sense to me.

The model I'm used to is that doing mitzvos refines one's soul, and 
having a more refined soul enables the receipt of schar, both in olam 
hazeh and in olam haba.

In order for schar to be transferable doing mitzvos must have no logical 
relation to improving one's soul; instead mitzvos must be purely 
arbitrary.  It is true that one can construe an opinion in Hazal to say 
that (see MN 3:48 citing Berachos 33b and see the Ramban's critique in 
Ki Seitzei 22:6), but this opinion seems to be ignored in most 
contemporary discussion (and the Ramban denies that it exists).

Can either of you explain the "bank account" model in a more 
satisfactory way?

David Riceman