After importing do the imported cells show Text under menu format/cells?

I don't know how it happened but you can at least deal with it if you
don't figure it out. I'll address that, though hopefully someone else
who's done a lot of web-grabs will recognize your plight and explain
just why it happened.

Are there extraneous characters on the labels, such as a trailing minus
sign?  If not, then they may look like "labels" (text) but you can still
do your math on them.  Sometimes Excel "imports as text" and the usual
remedy is to click a blank cell, copy it, select the imported values,
and Paste Special, clicking on the "Add" check box.  This would "add
zero" to each of the selected cells, ridding the text aspect.

The Text format can have another nasty effect that may be what you're
running into.  If the cell you do the manipulation in ("the formula
cell") is text format (check menu format/cells/number), then if you type
=a1*1.1, then that's all you get - no multiplication or math is done at
all.  You need to format the formula cell as General or Number before
entering the formula in that situation. (Or fix them after the fact by
replacing = with = .)

Finally, if there are those extraneous characters, they can be stripped
off using worksheet functions like LEFT, MID and LEN. Fortunately these
are not necessary to handle commas.  If cell A1 shows 175,000, you can
still go =a1*1.1 (again, enter the formula in a nontext cell). (However
keep in mind that there may be invisible characters picked up from a web
page, often at the beginning or end of the range.)

Obviously you'd like to avoid all of that and just get it as numeric in
the first place. My guess there would be that you're not selecting
exactly the same data to copy/paste. See if your situation persists if
you select EXACTLY the same thing. My recollection is that with some
data transfers that Microsoft looks at the first value copied and
decides text vs. numeric from that - but I'm not certain if or when that
occurs.  Maybe you're copying text headings in one situation but not the
other?