It is advantageous if the wicket remains almost same throughout? What if wicket is slowing down every over and batting first is relatively easy. Will it help chasing side to only know the target where Dravid can become Kumble with the ball?
There is no alternative for a complete game, therefore DWL (or any other method) is just to complete the game, otherwise we'll have to abandoned an ODI game even if it's washed out after 99'5 overs, with less than 7 runs at stake.
IICRC, there had been 4 methods used so far - in olden days, in ENG, they used to carry the game (in case of weather interruptions) to 2nd day, which isn't possible in modern days of packed schedules of broadcasters. Also, it's not fair for the spectators and organization costs increases massively.
First mathematical method used was straight line method - chasing team's target is set at the rate 1st team scored for the number of overs they are to bat. This is the worst of the methods - in a remotely even contest, side batting 2nd will win 100% times. This rule was exposed in 1988 WSC 3rd Final at SCG. On a dry wicket, AUS batted first and were like 240-3 in 40 overs, then rain came for 4 hours ...... WIN's target was set 121 in 20 overs and they blasted it. Richi Benaud went crazy with the rule and I completely agree with him - AUS could have scored 319 that day, and WIN would have been chasing at 6.4 for 50 overs on a dry surface against 3 spinners .... instead they were given an asking rate of 6.0, for 20 overs, on a wet out field and soaked ball.
Then, ICC changed the rule which was used in 1992 WC - thanks God that, it was exposed soon and replaced immediately after WC. That rule was too skewed to side batting first - they used to curtail the least scoring overs (& runs) for a rain curtailed game. For example, take that SAF-ENG game - SAF bowled 2 maidens (0 runs), so, when the game restarted with 2 overs lost to rain, SAF lost 2 overs but target wasn't reduced. Same equation cost IND the Gabba game - they lost by 1 run (to AUS), when 3 overs were curtailed, but target reduced by 2 (AUS's least scoring overs were 0, 1 & 1). In fact, had the game between PAK-ENG (Adelaide, PAK all-out for 74) went for 20 overs for a result, ENG could have been screwed - their target for 20 overs would have been still something like 74 (bowled 10-12 maidens and PAK was all-out inside 35 over)!!!!
Then, they came with a statistical model which considers wickets at hand (or lost), and trends (of contemporary game); and they project a possible 1st innings total for a given situation, then pro-rate the revised target, which is subject to wickets again for the chasing side (if it's interrupted again in between). Also, DWL method allows possible maximum overs - today IND batted 17 overs in response to 16'1 overs; in any other method, their target would have set for 16 overs (only 1 over in case of T20, but in ODI it's a factor).
It's not perfect, but by far the best method. You can check it yourself - take few close games (from past, result know) and run DWL calculation (it's available in net) for different points of time (say after 10, 25 & 35 overs of both innings) - you'll see their projections are remarkably close for most games.
) DL being used agaisnt SA in 1992???? I have heard enuff
