I don't know your age or recovery ability but a lot of cat 5's would be doing more harm that good by adding to 220 miles a week.I would like to look at adding another workout into my weekly schedule
Again, I don't know. But you should probably look at substituting rather than adding.
I ride around 220 miles a week myself but that's just because I like to ride. If I was serious about maximizing my racing ability less would definitely be more. 220 is good for base training. For adding to speed in the middle of race season, generally not so much for cat 5 level.