If you think the Suunto is giving you too much deco you can adjust the aggressiveness of the algorithm. Have you considered that maybe the Shearwater wasn’t giving enough deco? What were it’s settings. I’m no Suunto fanboy but they do work for the majority of diving, sure once you start getting into deco territory other things may work better to your liking but there in nothing inherently wrong with Suunto. It’s when you have mixed teams with divers using different algorithms where some of these weaknesses are exposed, if you were both diving Suunto then you may have been ok with it.