So my question is: Can a layout have multiple merged fields formatted differently??
You can't as FileMaker sees the block of layout text as a single object. How do your text fields "go astray"? Can't quite see how specifying a number format for your currency fields will have a negative affect on your text fields unless one or more of them are of type number instead of text.
The workaround is to do your formatting before including the data in the Merge text. Calculation fields can be defined that round numbers to specific numbers of decimal places and include dollar signs and the needed trailing zeroes after the decimal point. You can then include this calculation field as the merge field in your text.
Thanks for the reply, I've sussed it. A mixture of being too close to the problem, leaving the room and having a cup of tea for 30 mins. Then taking a deep breath rounding all my number fields and sorting out the trailing zeros. My text fields going astray were to do with me not putting data in them to display in the first place..! doh..