A Real Wireshark Quirk

Ok, what is the deal with this? (By the way, I don't care if this sounds like mindless rambling. It's late on a Saturday night and I'm analyzing traffic. W00t.)

Here are TCP flags from a random segment.

    Flags: 0x0018 (PSH, ACK)
        0... .... = Congestion Window Reduced (CWR): Not set
        .0.. .... = ECN-Echo: Not set
        ..0. .... = Urgent: Not set
        ...1 .... = Acknowledgment: Set
        .... 1... = Push: Set
        .... .0.. = Reset: Not set
        .... ..0. = Syn: Not set
        .... ...0 = Fin: Not set

TCP flags occupy 1 byte, and that's it. Why does Wireshark/etc. say

    Flags: 0x0018 (PSH, ACK)

Why not

    Flags: 0x18 (PSH, ACK)

that instead?