Yes, you're right. However, I wanted to use my existing 110bcd 4-bolt Powermeter, and I couldt only find 5-bolt offerings from Ratio. Also, by now you can get flattop-compatible chain rings in any standard (also 4-bolt) on Aliexpress for roughly half the price (hopefully not half the quality

), which is not the case for ekar compatibility...
I'll post here to let you know if the setup will work well.
P.S.: I want to use it with the wheeltop GeX, and I couldn't find any references for Ekar chain compatibility with the lower wheeltop pully, whereas there are reports on GeX+flattop chain which seem to work well...