Remove some unnecessary weights to variables; this should make it easier to gain optimal schedules. Specifically, I was previously encouraging jobs to all finish as quickly as possible. However, that's not necessary for an optimal schedule. So long as the LAST job finishes at the optimal time, I should not care about when the previous jobs finished. At the moment, so long as the job finishes before the lower-bound of the optimal time, the job does not get penalised.