I don't know about your acars, but mine
has a nifty little feature
position
wx...including ice, turb, other...just highlight and enter...
and takes about 10 seconds or less to send a pirep...and if one guy is flying witht the plane on autopilot it doesn't take long for the other guy to send a message...perhaps hoping that OPS would send back some knowledge like: company reports ride 50 miles west good