My understanding of "relevant amount" for those who signed CoS08 in lieu of taking SLS is the amount of SLS they WOULD have taken had they NOT signed CoS08. So, in plain English: 3 weeks pay for FOs and 4 weeks pay for CNs
In other words, those who signed CoS08 in lieu of taking SLS will get a bonus of 3 weeks pay or 90% of 4 weeks pay in April. However, those people did NOT get 3 or 4 weeks of extra vacation.