On second thoughts, the extra information is probably less complicated, Steve can say "I'm available between @300 and @1000" (maybe he keeps odd hours), and this knowledge plus a glance at the current time can tell me whether I can call Steve.
Steve could also just tell his availability in UTC, and the same lack of maths is needed. Although, we still need maths because most of us don't use UTC time, in the UK only half a year as well. Except Icelanders...
On second thoughts, the extra information is probably less complicated, Steve can say "I'm available between @300 and @1000" (maybe he keeps odd hours), and this knowledge plus a glance at the current time can tell me whether I can call Steve.
Steve could also just tell his availability in UTC, and the same lack of maths is needed. Although, we still need maths because most of us don't use UTC time, in the UK only half a year as well. Except Icelanders...