i dont think it is as simple as that. Yes, we offered Moses 1.3 but you cant then add the value of the players leaving. That 1.3 probably factored in Brooks either leaving or halving his contract value and may have even considered plans to release players e.g. JOfa to accommodate. I think it's more likely you could add 500K for Brooks going. Talau wouldnt be on much as such any replacement would be of similar value, that's a scratch. JOfa being released may have freed up some space but it may also already be allocated to upgrading players earlier than originally planned e.g. Bula.
I would be surprised if there is more than 2M available and i think from memory 4 spots left in the 30 (happy to be corrected on this number by someone that has the list in front of them).