Mevo+ device placement

[mntlblok]

https://www.flickr.com/photos/mentalblock/53234548070/in/album-72177720311708479/

If I were to place a Mevo+ device where the PRGR sits in this photo, would that be a problem? I seem to have maybe read somewhere that the surface between the device and the ball must be continuous - with no gap as exists in this photo. Is that so? Having trouble getting a clear answer from salespersons. . .

BTW, have found that I can get the PRGR to read (mostly) by placing it on two or three layers of those mat inserts - with the gap in between.

[mntlblok]

https://www.flickr.com/photos/mentalblock/53234190761/in/album-72177720311708479/

Found this - though not easily. Asked about this on the "chats" on two different sellers' websites. One was listed as an "expert". Apparently neither had access to owner's manuals. A bit frustrating to try to make a purchase without adequate information. . .