qusetion on A4o vs A8o vs 9Ts

[Jinx]

I just ran my pokerstove and it gives that A8o has more equity against 9Ts than A4o does against 9Ts. Thinking about it this doesn't really make much sense, since the A4 has the wheel draw, and it seems like it doesn't matter if the lower card makes a pair for the ace hands. Could someone explain to me why A8o is better to have than A4o against 9Ts?