As I said, DFM, I wasn't querying your maths so much as musing whether the scoring system sufficiently rewards specialist/top order batsmen. As you observe, the role tends to result in a slightly lower scoring rate than those who come in later. A top order player scoring 49 off 40 balls will score 59 points. A player who comes in at the end of the innings and clobbers 2 sixes, a 4 and holes out and gets out scores 16 runs off 4 balls and gets 46 points - not that far behind really, and I'm not sure in proportion to the value of their innings.
Similarly with the bowling - it seems much harder to me to bowl 4 overs economically than it does to bowl 2, especially given if you're bowling out, you are almost certainly bowling towards the back end of the innings where strike rates go up and batsmen are taking more risks (I guess you could argue you're more likely to pick up wickets to make up for it) - how many times do you see a bowler keep a lid on things for the first spell, then come back and concede a couple of boundaries in their 4th over and have their figures ruined? Under the current system, a part-timer who bowls 2 overs for 0-14 in the middle overs picks up 20 points, one who bowls 4 overs for 0-29 gets 10 points while a player who bowls 4 overs including 3 at the death and records 0-33 gets diddly squat - doesn't seem quite proportionate.
I guess the lesson is pick the bits and pieces players for long series like this, as they've got more chances to steadily pick up points, although the ones I did pick, like Christian, aren't doing much anyway

. Also don't pick players who have signed up to multiple domestic franchises
