Scalar Functions & Limits

[Fuzzmaster]

Having fits over something that should be dirt simple; (...) = Left Out Identical Bits:

SELECT ALL  INV.Ship,... INV.Amt FROM PUB.Invoices AS INV WHERE ...
or
SELECT ALL  INV.Ship,... INV.Amt FROM PUB.Invoices AS INV WHERE ... ORDER BY 1

Returns 1200 Rows.

SELECT ALL INV.Ship,... INV.Amt, ROUND(INV.Amt,-2) FROM PUB.Invoices AS INV WHERE ...
or
SELECT ALL INV.Ship,... INV.Amt, {fn ROUND(INV.Amt,-2)} FROM PUB.Invoices AS  INV WHERE ...

Returns 300 Rows.

SELECT ALL INV.Ship,... INV.Amt, ROUND(INV.Amt,-2) FROM PUB.Invoices AS  INV WHERE ... ORDER BY 1

Returns 0 Rows

Is there a limit imposed on results when using dirt simple scalar functions?
Since when does an Order By clause cause zero results? or
What incredibly simple blunder am I making here?

I already feel like a complete git, so emasculate at your leisure (so long as you include usefull insight).