Giving members a discount

A concession is money off. It is its own thing rather than a negative charge, and it appears as its own green line on the invoice, under whatever it is coming off.

Find them under Billing → Concessions.

Setting one up

• A fixed amount or a percentage. £10 off, or 50% off.
• Who gets it — a member group, or every plot holder. Groups are the usual answer: make a group called "Over 60s", put people in it, and point the concession at the group. Adding somebody to that group is then the whole of the admin.
• What it comes off — the rent, the other charges, or both.
• Whether it repeats yearly. This is on by default, because a concessionary rate normally carries on from year to year. That is the opposite default from a charge, and deliberately so.

A fixed amount can also be set to count per plot rather than per member. A percentage cannot, because a percentage already grows with a bigger bill — counting it per plot would discount twice.

It can never take a bill below zero

Stack two large concessions on one member and the second is trimmed to whatever is left. Nobody is ever invoiced for a negative amount, and Allotmin never owes a member money by accident.

Giving it to one person

Somebody qualifies half-way through the year, or qualifies for a reason no group covers. Use Apply to a member — it does not check the group, so it works as a deliberate exception.

After you change the amount

This matters more here than it does with charges. Applying a concession only ever adds; it does not revisit lines already written. So if you increase a discount and do nothing else, the people who already have it are still being overcharged at the old rate.

Press Re-sync after editing the amount. The message after you save says so too. As with charges, it only touches the year you are in.