Different number formatting seen in native app vs. mashup

[jeremydoherty]

I have several charts and KPIs for which the number format appears differently in a mashup, in which it is brought in as-is, vs the native app.  The formatting is specified with Number/simple (also tried Custom), and appears correct in the native app:

but looks like this in the mashup:

According to the person doing the mashup part, there is nothing applied to the object which should override the formatting.  Any suggestion?  I would like to use the 'number/simple' formatting, because it is the only one we have found to export to Excel properly.  This is v 3.0.

Thanks