I can do maths.
My point was that an extra 5% is not a huge amount for those looking to buy for the long term given that, in time, it will all even out to a few cents per day extra. Removing speculators/hoarders has to be the driving force behind price stability.
Anyone unable to find the extra 5% shouldn't be looking to buy at any price, let alone the $1m of your example.
Stamp Duty is a tax on mobility that reduces liquidity in the market, and fuels price rises.
The first four homes I owned in London were within a mile radius of each other. I 'traded up' by buying well.
The flip side is that PRs will be pressured to not move. Just greeeeat if you're now a married couple with two children having far outgrown your 2-bed 'starter home'. And now with one adult working (as opposed to the both of you you started out with), as the wife looks after the children, you are in a tax-trap.
p.s. This also strikes me as 'taxing people for their own good', but if as above you remove the good, you're just left with higher taxes.