Onkyo Binding (or direct chromecast) not sending proper volume signal

I have an Onkyo TXRZ810 receiver, and Openhab 3 recognizes it just fine as a chrome cast device, and I also added it using the Onkyo binding which also worked, and allows for more visibility under advanced for the points/channels available to multi zones.

I don’t seem to have any problems with power, input etc., however when I add the volume control for zone 1 to HABPanel, it can’t send any volume past 50, and is always sending half the number I select. For example, it I select 50 on the slider style, or the knob style, the stereo sets to 25, if I set 80, it sets to 40. If I set 100 it goes to 50.

I tried changing the range to be 0-200 instead of 0-100, but nothing happens when you select anything over 100.

Any advice?