Do you think you will run afoul of Microsoft for using their trademark in your product name? Is there a lawyer here who can chime in?
Gleaning from that I'd say that it would be alright to name a product "Analytics Panel for Excel" but with "Excel Panel" they might run into problems.
At the very least they probably should mention Microsoft trademark ownership somewhere on their site.
Maybe "Analytics Panel for Excel" would be safier, as @BjoernKW suggests.