CAS, You are right with your math and thank you for another perspective. I was using those SIMPLE examples because they offered a little of everything, that I look at, WHEN I LOOK for a trade. I look probably once a week. I got tired of sitting in front of my computer all day looking for trades and when I didn't find any for a while, trying to make something happen and losing. Also, When I have up to twenty positions open, if I get into micromanaging them, I'll lose my mind. I let them do what they want because they will, I just go along with the flow. I'm still making good money, and out living my life.
You mentioned interest. Sometimes you pay it and sometime you get paid it. I don't factor it in when I trade the majors because the interest charged, or paid, is miniscule.
I gave simple examples with reverse correlated pairs, my bad. I just wanted the concept to be understood. Apperently my audience may be a little more advanced, but unfortunately my trading strategy isn't so here's another chart.
This is the current weekly GBP/NZD. The color coding and shapes are the same as above. The first trade profited about 2000 pips over about 20 weeks=20 pips per day + 3% rollover per day. The second trade was about another 2000 pips over 18 weeks=22 pips per day + 3% rollover (I don't care to know how to figure the actual number related to pips) per day. Third trade another 2000 pips over 18 weeks ( there is a patten developing) 22 pips per day minus the 3% rollover. So cancel the rollover I gained in one of the previous trades and I'm still up on rollover. Trade 4. About 4000 pips in 25 weeks. 32 pips per day. Paid on the rollover.
Time I looked at this position per week (5 min) x total weeks (81=1.5 years roughly) = 405 min / 60 = 6.75 hours of face time this instrument received in a year and a half. 10,000 pips in that 1 1/2 years or 6.75 hours face time. 10K/6.75= 1481.48 pips/hour of face time for that instrument and ahead in rollover. I'll take it! Numbers are fun.
I'd say with all the positions I have open at any point in time probably take 2 hours of my time per week, instead of days and days like they did before.
Trade how you may... I've got things to do.