[-] Separate adding and subtracting planes to/from UM

[sanabas]

The intent of the limited calls is to stop people endlessly refreshing the UM, and to stop cheats designing bots to grab more planes from the UM.

However, because I think that when the brokers update the UM they add and subtract planes at the same time, this means there is a workaround to check if there's been a drop without using one of your seven calls. And probably also possible to design a bot to do it. Which will now make me curious about those who seem incredubly lucky at acquiring UM planes.

Anyway, the workaround:
Look at the UM, see 1500 planes.
Look at the UM 2 minutes later (or whatever short but slightly random interval you assign to your UM bot to avoid it looking too regular), see 1490 planes because some are grabbed.
Look 2 minutes later, now see 1475, again some are grabbed.
2 minutes later, 1410, brokers have removed some, therefore they've added some, therefore use one of your 7 calls because there has been a drop. Grab planes for yourself, now there are 1470 again, repeat for first 2-3 game years.

If the brokers purging unsold planes and putting them back in storage happened at a different random time to the refreshes, or just happened once per game day/week at a fixed time (say midday wednesday, or if the 20-30 longest-listed planes were removed every day at the 12:00 staff payment), it'd remove the ability to check for a drop without using one of your 7 calls.

[Sami]

The processes are already separate. But often occur at the same time .. Adjusted it a bit.