I have a project that I now maintain on just 2 hours a week... But I worked on it for 4 weeks, 10 hours a week... So that is 136hr/y. Revenue for the past 12

I have a project that I now maintain on just 2 hours a week... But I worked on it for 4 weeks, 10 hours a week... So that is 136hr/y. Revenue for the past 12 months is £26,500 26500/136 = £195ph