OK, I see what you mean now Wespi.
I'm not really a systems man [I'm always running one or two though from interest]. I avoid last start winners as a system filter and rarely back them from handicapping either as they attract too much attention and have earned a weight penalty [poor value]. If I think they will win I ignore the race.

2nd. and 3rd place-getters and first starters are always worth a look at for systems or handicapping. 3rd to 5th up though, are always worth a close look for fitness reasons.
Many runners have their win[s] for their current campaign [if they have a win at all] at their 3rd., 4th, or 5th, run in from a spell as they are going to reach fitness peak during those runs, keep it for a few more maybe and all down-hill after that. I'm very wary of 2nd. up runners though, as it's often a flat run unless the horse has a very good 2nd. up record.