I would be interested in the answer to the question 'who owns the KH'? If it's owned by WTBTS, cost of refurbishment would be theirs, not the congregation's.
And how is the loan/interest payments dealt with in WTBTS accounts?
Up until the early-mid 80s, individual congregations built and financed their own Kingdom Halls. Sometimes two or three congregations would consolidate their funds and labour and build a single shared KH between them. Then around 1983, a new Simplified™ arrangement by the WTS was introduced, which would allow congregations to borrow money from the WTS in order to build or renovate KHs.
The way the new Simplified™ arrangement worked was that the congregation was responsible for purchasing the land on which to build the KH. The WTS uses the property as collateral to secure a loan up to the amount paid for the property (this is not spelled out to the congregation). In other words, if you paid $100K for the land, the WTS would lend you $100K toward the building.
So your KH gets built. Everyone is happy. The congregation is required to remit to the WTS a per publisher amount each month to cover the cost of the loan. This is where it starts to get tricky... because remember... the WTS has a Voluntary Donation™ policy, so they can't outright demand payment from each publisher. If the congregation doesn't have sufficient donations to cover their monthly mortgage requirement, the WTS can foreclose on the loan.... and they pwn the KH and the land upon which it sits. And here's the kicker... rather than forcing the congregation(s) to sell... they just charge RENT instead... at the same nominal per publisher rate as the mortgage payment. And the common publisher is none the wiser.
It's also happened with congregations who wanted to renovate their existing KH (owned outright by the congregation). The congregation raises 50% of the money required for renovations, and the WTS loans the other 50%, using the property as collateral. If the congregation can't maintain the the payments once the renovations are complete... guess who pwns the KH?