This may just be another difference between the SDK and the SWQL running in Orion.
I have a query set with ROUND(<column>,2). Literally the same query is pasted into both - running SAM 6.2.4.
In SDK:
In the Orion resource:
Report as bug?
Yes, I would report that through support.
Possible workaround for you to try: put TOSTRING(ROUND(<column>, 2)) in your query. This will cause SWIS to return a string to the client instead of a float. If SWIS does a better job of that than the Orion website, this will help. Otherwise it will just make it worse in SWQL Studio as well.