Depreciation schedule unusable

Hello! I am trying to create an asset and the Depreciation scheduler will not let me do what I need to. Here in Canada, depreciation is a fiscal issue and is regulated. For example, computer hardware has a depreciation rate of 55% per year, and the first year is halved. This is basically Declining Balance method. So for a 100 $ device bought today, the depreciation would look like this:

How can I change the declining balance rate, and use a half-year convention during asset creation? I can’t even use manual mode to set fixed amounts on fixed dates, every time I save, it gets reset.

I tried using two rules, one manual for the current year, and one written down for the next years, but the first rule is never applied.

Thanks,

Edit: One way I found to do what I need is to set the date of start of usage to July 1st, with a written down depreciation rate. However, that would make things awkward in the case where I’d get rid of a new asset within the same year.