No problem, exGST is fine. What is the ABN for my accounts.
Although you are not charging, you of course also can't claim your GST off payments, like rent either.
The $150,000 is only the point where you are required to, you still can optionally.
If you charge now
$110 no GST
and payments for rent is
$110 with GST
Then you are even.
If you register for GST then
if you now charge
$100 + $10 GST - you owe $10 to ATO
and payment for rent is
$100 + $10 GST - you now owe ATO nothing
So I totally understand avoiding the fuss of BAS. The only disadvantage is the 10% paid extra by professionals, who could have otherwise claimed that. But since the fee is so low, maybe this is not a concern either.
Something worth adding to your list to review once a year, in case the numbers change. e.g. if you get a grant, but still have to pay bills, you don't pay GST on the grant, but you still could claim off the payments and be ahead.
Scott