Sure - I was just making sure you hadn't set the altitude of the course (e.g. 10000m above sea level) to be the terrain height as that would definitely make the raise tool very sensitive.
As yes - the amount raised each click is dependent on the terrain height set
per click raise = terrain height * opacity / 10000. (approximately*)
For a terrain height of 220m and opacity = 100, each click = 220 x 100 / 10000 = 2.2m.
or if opacity = 0.5, then 1.1cm
Now 220m between the lowest point on the terrain to the top point is large - I assume you have a large mountain on your terrain as even the rolling Augusta has only about 80m of elevation change. But it will make your tool more sensitive than what you are used to if you're previously had the more common 30-50m type terrain heights.
I still think 1.1cm however is manageable. Can you post your raise tool settings as if I type in 0.5, it will be displayed as 0, however 0.5 will be used. But I can also type in 0.25 and it will be used too (still displayed as zero) whereas you say 0.5 is the lowest you can do.
* These are approximate because our raw maps represent 16 bits of height = 65536 steps. So these clicks above will round to the nearest step = 220m/65536 = 3mm, and possibly some more because of rounding in the slider value.