We checked the code in the UpdateManipulationAdorner methods. We can confirm the purpose of the Floor() and Ceiling() roundings you mentioned is to resolve blurring issues. These issues cannot be easily solved with UseLayoutRounding or SnapsToDevicePixels properties that come directly from the WPF Framework.
You can log a feature request in our feedback portal
and you can describe in it the scenario you need to be supported. Later we can approve it and if it gathers enough votes we will consider implementing it.
Check out Telerik Analytics, the service which allows developers to discover app usage patterns, analyze user data, log exceptions, solve problems and profile application performance at run time. Watch the videos
and start improving your app based on facts, not hunches.