There is a possibility that the "WE" reference was due to the fact that the student was actually doing the training for his/her multi engine commercial rating. I have cut and pasted the regulation (and included all relevant lines):
Subpart F--Commercial Pilots
Sec. 61.129
Aeronautical experience
(a) For an airplane SINGLE -engine rating. Except as provided in paragraph (i) of this section, a person who applies for a commercial pilot certificate with an airplane category and single-engine class rating must log at least 250 hours of flight time as a pilot that consists of at least:
.
.
.
(4) 10 hours of SOLO flight in a single-engine airplane on the areas of operation listed in Sec. 61.127(b)(1) of this part, which includes at least--
(i) One cross-country flight of not less than 300 nautical miles total distance, with landings at a minimum of three points, one of which is a straight-line distance of at least 250 nautical miles from the original departure point.
OR FOR MULTI ENGINE, > > >
(b) For an airplane MULTI engine rating. Except as provided in paragraph (i) of this section, a person who applies for a commercial pilot certificate with an airplane category and multiengine class rating must log at least 250 hours of flight time as a pilot that consists of at least:
.
.
.
(4) 10 hours of SOLO flight time in a multiengine airplane OR 10 hours of flight time performing the duties of pilot in command in a multiengine airplane WITH AN AUTHORIZED INSTRUCTOR (either of which may be credited towards the flight time requirement in paragraph (b)(2) of this section), on the areas of operation listed in Sec. 61.127(b)(2) of this part that includes at least--
(i) One cross-country flight of not less than 300 nautical miles total distance with landings at a minimum of three points, one of which is a straight-line distance of at least 250 nautical miles from the original departure point.
Hope this helps clear up what seemed to be a violation of a FAR but could actually be totally legit (especially since many flight schools do the MULTI commercial first, then a single engine ADD on).