yes, it was such a weird conversation! I looked pretty closely at Nav today and measured him with a weight tape. The tape came to about 1020 which I believe is at least 100 lb lower than I want him to be, but he also doesn't look especially thin. I'd mark him as about a 5 on the body score scale. It would be a little easier to tell if he wasn't so fluffy with winter coat - he's starting to shed though! Last time I taped him was last summer when he had been out of work and was pretty overweight, at about 1285.
Anyway, we upped his feed a tiny bit, don't want to upset him with too big a change quickly, so he now gets about 4 lbs a day (split between two feedings), plus a couple flakes of hay in the stall with meals, free choice hay in the pasture, and what little pasture we have right now - I can't wait for spring to get here! I may see if I can get some good body photos of him to post for critique. I know it's easier to tell about those things in person, but couldn't hurt to try and get some other opinions.
I rode today, Nav was really good! We reviewed some of the things we did in our lesson, mainly the transitions within trot, and energetic walking on a loose rein. I hadn't ridden since our trail ride last Monday, but we have another lesson this Thursday and I didn't want him to go into that without some warm up rides. It's been cold here lately and between that and work I haven't ridden much. :( But I made myself go today, it was in the mid 40s and sunny so not too bad, and it's just supposed to get warmer this week! I will update with how the lesson goes.