If I just use the numbers you have given above, this is how I see it. I'd be happy for you to correct me if I'm off the path here.
Using the tin at 1.8kg and providing 80% solids, as per your assumption, gives 1.44 kg solids plus 1.0 kg sugars, M.E. = 2.44 kg.
Total volume of liquid was 22.5...