I am not getting into the facts and figures debate, but there are a few nuances that you might consider factoring into your assessments and comparisons to ensure ceteris paribus.

1. How is an upfront payment to a signing player amortised over the life of the contract in comparison with a payment to another club? It seems to me that a payment to a player is likely to be reflected differently to the payment to another club.

2. An upfront payment is likely to be upfront, whereas a payment to a club is often spread over a period of time.

3. A Contract is rarely allowed to run full term nowadays. Resale value is a consideration.

The upshot is that if you purchase a player for 10 million on a 5 year deal, it is different to paying an upfront fee of 10 million for a free agent.

I think these debates should really bear a proper consideration of the business aspects. As interesting as it may be, it is important that the comparisons between what we could do, and what we have done at least pays respect to our general lack of understanding of football as a business.

I think you are crystallising the difference between running a football club and being a supporter.

Those running the football club are having to make decisions about what to do, and not do, based on a complicated set of criteria depending on what they are faced with at the time. This includes cash and FFP considerations. In other words they need to consider what is possible all things considered.

As a supporter, we can create an entirely artificial set of criteria, based on the facts “as far as we are concerned”.

For example, Kouyate’s £10 million is amortised at £2.5 million a year. Bernard’s is £10 million up front - so the cost of Bernard this season would be £7.5 million more.

Basically, when you pay in installments, you are reducing the stress on your cash in the bank. So, a £10m fee for a player in the accounts will be based on the contract length rather than what you paid, so if it's a 5 year contract then £2m will show in each years accounts, whether you paid it up front or not. I imagine an up front payment to a free agent would be treated the same too as you could argue it is basically a transfer fee.
That's why the first thing you should look at when a company releases their accounts is the cashflow statement to see how much money they've got.

Yes. This is precisely the point. Unless you know the precise deal, you can’t know whether it is comparable or not. It can cut both ways, but without the full knowledge, everything else is just speculation.

Clubs can use factoring agents (FA). E.g. price = £9M. FA facilitates club lump sum so can pay price in full. Club pays FA £10M over time.

It might actually be a case of Wolves couldn't afford his release fee in one payment which is set at 18 mill. So for them to get their man they have had to negotiate a fee with the club over installments. They and Bro may well actually value him at more than 18 mill but that was the fee agreed as a release fee when he signed his Boro contract.