What actually matters is what is in the player's Contract that is lodged with the NRL, that's what they use to determine Cap compliance.
You actually don't have to pay the player the same amount every week/fortnight/month. You could pay them the whole annual contract value on 1st November and then pay them nothing for the rest of the year.
You can actually give the player more money (than the contract value) in one year but you would have to call it "a loan" and charge them interest. Then deduct the same amount the following year to repay the loan.
The above happens quite often, for example when players are buying a house and need the deposit. It's all up to the Club's cashflow position and due to the strength of the Leagues club we are able to pay in advance. Just have to inform the NRL and comply with the interest requirement.
Keeping in mind the reason for the NRL banning front and back loading is to avoid a team having way over the Salary Cap in 1 year and then being way under the cap in other years (before or after). Can't have a team with, say, $15m worth of players this year and then $9m the next/previous year.
There appears to be an allowance for back loading, but it has to be a small % of the contract value, has to be justified and the NRL has to preapprove it before the contract is lodged and signed. By justified you don't get to back load a contract just so you can exceed the Cap limit in one year and be below the Cap limit in another year. For example it would be easy to justify having a young player with an increasing contract value due to them gaining experience etc. A seasoned long term NRL player would be much harder to justify.
The grotesque back loading (a la Hasler) is not allowed. Plus having multiple players with back loaded contracts is not allowed, it has be the exception not the rule.
I have no experience with front loading, but I can't see the reason for it to be allowed, much the same as back loading.
Always a Bulldog