Here's the AA UK-specific baggage info for excess, overweight, oversize:
Code:
EXCESS/OVERSIZE/OVERWEIGHT
---------------------------
.
. * MAXIMUM 3 EXCESS PEICES
. * OVERSIZE IS 63 - 80 INCHES
. * OVERWEIGHT IS 71 - 100 POUNDS
FROM/TO:
.
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I BAGGAGE I BWI I OTHER I YYZ, I YEG, I
I I BOS I U.S. I YUL I YVR, YYC I
I I DCA I CITIES I /CAD/ I /CAD/ I
I I IAD I /USD/ I I I
I I EWR I I I I
I I LGA I I I I
I I JFK I I I I
I I PHL I I I I
I I /USD/ I I I I
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I OVERSIZE I $90.00 I $110.00 I $140.00 I $165.00 I
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I OVERWEIGHT I $270.00 I $330.00 I $140.00 I $165.00 I
I I I I I I
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I EXCESS I $90.00 I $110.00 I $140.00 I $165.00 I
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I EXCESS/ I $180.00 I $220.00 I $280.00 I $330.00 I
I OVERSIZE I I I I I
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I EXCESS/ I $270.00 I $330.00 I $280.00 I $330.00 I
I OVERWEIGHT I I I I I
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I OVERSIZE/ I $270.00 I $330.00 I $280.00 I $330.00 I
I OVERWEIGHT I I I I I
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I ALL OF I $270.00 I $330.00 I $420.00 I $495.00 I
I THE ABOVE I I I I I
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So, as far as I can work out, the charge should have been $330. Not $390.