From Hockeyviz. Goals sore per 100 unblocked shots throughout his career. Basically, black shading means he's scoring more than his expected, red shading means he's scoring below his expected. Given his entire career has been in the black, it's notable that it's dropped so much so quickly...
This one is from Evolving Hockey. They split their GAR metrics into expected vs actual. When reviewing ES offense, you can see that the GAR is significantly better than the xGAR. EH does not have an extensive write-up for their GAR model so my interpretations are based on assumptions. Jfresh uses Top Down Hockey GAR model on his cards. It looks like that is more of an all encompassing model, and does not split up the expected -- even so, the mix of EH's GAR and xGAR are inline with Top Down Hockey's model.
My concern with couts' and his future ability to produce offense, however, comes from this data, his tracking data from All Three Zones, and just the eye test. The fact that his xGAR and GAR are so wildly different might be an indicator that he's beginning to decline - but I also believe this season was always just about staying healthy. Let's see how he looks next season.