It looks interesting - but I'm not familiar with banking in Spain and it depends with what you are comparing it with.
But a basic sniff around throws up the following which seems to be a TYPICAL observation:
Bank charges in Spain are quite high and free banking is very rare. It's
quite common to be charged for everything, including withdrawing money
from ATMs. When using ATMs you need to check what the charges are as
they vary between systems.
http://www.idealspain.com/pages/finances/banks.htm
Congregation accounts should still be running with a regular balance of around 5,000 to 7,000 Euros - which isn't bad - it is also unlikely they will 'default' and go overdrawn - they also probably have a lot less transactions going on than a typical personal account?
So the next question is what do the congregations have to pay for - and how many payments do they make.
I note that you have not included a copy of the attached banking agreement showing the costs (and ideally the previous agreement showing the previous costs)
BTW there is also the following paragraph in the letter:
A favorable aspect of the new agreement is that all the conditions included are centrally registered for all of our accounts. Until now, some of the conditions had to be recorded manually at one location and another. When this was not done, commissions were often charged outside the terms of the agreement, and then it was necessary to request the manual refunding of these. In many cases the refund was not possible or was only attained with great efforts. This same situation recurred again and again, until the conditions were registered permanently at all those locations. Now, as we indicate, the bank has confirmed that all the conditions of the agreement have been recorded in a centralized way for all our accounts. We believe that this technical advancement will avoid the greater part of the incidents.
It seems that the individual banking branches are much more 'independently' run, even within the same company, than what might be expected in other countries.
There is zero costs for transfering monies between WT entities - ie between congregations (for example to a KH Operating Account when a KH is shared) or sending contributions etc etc to Bethel.
If there is a cost in paying bills (such as utility bills) then, if the congregation has funds, what is to stop them paying anually rather than quarterly?
Also - as long as there is a robust audit trial (with two signatures on everything), what about using donated cash to pay bills - though the US S-27 says you shouldn't.
Bank charges are interesting - Spain is one of the PIGS? -surely high bank charges ENCOURAGES residents to use a cash-based system? And a cash-based system is much more open to tax-avoidance issues - and I believe the BIG issue in Greece at the moment - to help stop tax avoidance - is the requirement that bank payments be made for paying wages, NOT cash.