Haha - just bustin' your balls man.

Your chosen metric (distance) was appropriate for your audience here. To me, a "metric century" is nearly meaningless without some indicator of effort - was your ride completed in 4hrs on a flat course with a tailwind, or in 4hrs with 5k+ feet of vertical?

If you're using power, it becomes totally objective: I did a 4hr ride at 70% FTP, for example - which is actually a huge effort that would put you in some serious fatigue for a couple days unless you have the aerobic base of a TdF pro. Even an average joe like you or myself should be able to ride for 3+hrs over consecutive days at 60%, as a counter example.

But not everyone has to become some data obsessed racer like myself . To each his or her own - and again, people will actually relate to you here if you tell them you rode a metric century vs. xhrs at y% FTP. I would post distance here for my rides but I don't even check anymore , haven't for years - no importa.