补什么差价？没有这一说 要么直接買商务 要么 Upgrade per chart + status order

Upgrade 是 mikes + cash. 前题是有位子放出來在 Upgrade Pool. 

https://thepointsguy.com/guide/american-airlines-mileage-upgrades/

拉下去看pecking order.  明显你是 general member no status.  要等所有 有各级 status 的 Upgrade requests 都 cleared 了 才輪到你。事实上 由 Plat 以下 長途 upgrade 机会基本为零。

Your chances of getting an upgrade (and a trick to help)

If you don't have elite status with American Airlines — and if there isn't upgrade availability at the time you're requesting — your chance of getting an upgrade is pretty slim. That's because the prioritization for upgrades on American Airlines is as follows:

有个表 自己去看

That's right. If you don't have AA elite status, your upgrade will only clear once everyone else's request has cleared.