You have made the mistake of using the HKIRD’s tax calculator which doesn’t calculate provisional tax. I’m sure you are very well aware the effect this will have on someone’s first year tax bill.
The first tax bill is normally issued the second year, around one year in arrears, and one in advance. I actually got my first tax bill in my third calendar year in HKG, with a year and a bit in arrears, and one in advance. I was asked to make that in two payments, first in the following Jan for about 70% of the total amount, the remainder about 3 months later.
My first tax bill was about 60k, I got paid less than todays TT cadets. Back then we used to get 6 months in the Headland when we started.
Okay, I got that wrong, it was 95% when I did it. With the 885k loan, they could easily still do a 6 mil property through HKMC, which still buys a fair bit in Disco Bay.