Also from the first post:

Each 'Firepower' point is then a membership point for the purchase of future exclusive items, and/or a $10 per year donation to the running of the club/site if the person nominates it at the time of payment. As such, people can top up their Membership 'account' at any time. (the annual donation concept would be phased out if ever in the future we had sponsorship or advertising to cover the running costs)
Which means, as per your scenario, both people are sending in the same amount, and both will have it reflected in their Firepower score (of 2), but the one who wanted to donate will have a + after their 2, leaving them with just a single Membership point in their account to use on any exclusive items.
Since I will endeavour to have exclusive items valued in multiples of $10, people who have membership points in their account will be able to use whole points to purchase items.

The Firepower score is basically your 'account'. Every point you purchase, is yours to spend later, if you didn't nominate one point ($10) as a donation. And donations can be one-off or annual - it's your choice.

As per post #3
Once payment has been made, you will need to email (address TBC) with:
- your username (and any payment reference name)
- your payment method
- your payment amount
- if the amount includes a donation, and if it is a one-off or annual donation
The 'payment amount' is a multiple of $10, with each buying a Firepower/Membership point. The fourth item above concerning a donation is voluntary, but if you nominate a donation to the board (of one point/$10), you would need to mention if it is one-off, or an annual donation.
Your account/Firepower will be deducted of one point after 12 months, but until then it will have a + next to your number so that you and I know that one point in your account is already being used. The remaining points are all yours to purchase stuff.