Hi Tony,
I sympathise having banged my head over the odd alignment of text but you need to, and you may have already done this, produce a replicable working example that others can see and use.
Your description implies something like the layout in the attached image. The text is in it's own box and the border is a frame object used to check that text isn't changing when published. That's unless the frame also changes but hey, this is basic science testing here
When published to flash, using any one of ten randomly selected fonts, the text is exactly the same every time and as it's laid out in Opus design mode. But, that doesn't mean it can't happen. I've had a two word title expand outside its box, but it was on a page with multiple animations, timelines and SCORM script - it was easier to just expand the box and live with the slight increase in space than spend the time working out why. I've also seen something work fine in everything and then display oddly in Chrome.
When you get to the point that it does appears that Opus is broken, and it does happen, you need an example that eliminates OS, graphics cards, machine, browser , bit version, flash version, etc...
The easiest thing as Paul highlighted, is to take a screen shot of what it looks like in Opus, what it looks like in flash and post this with the IMP to either DW or the forum. I don't know about the others, but I always give priority to questions that include a tangible example.
Mack
[edit] forgot example.