Typically I've found cross referenced parts work well. There is always that 1% chance a substitute part does not perform. I was able to track this flyback information from serveral sources, so personally I would not have a problem installing the substitue.
Over 27 years I've repaired a couple thousand monitors, replace hundreds of flybacks and often used substituted parts when necessary. Another thing that's VERY important in high voltage section repair is to find and replace any other componets that failed along with the flyback. Often a flyback will wipe out other parts when it fails. How often I've seen techs replace a couple of bad parts, turn on the monitor and fry the same parts all over again.
All bad parts must be identified and replaced before turning it on again.
It's also possible for other components to die that give the appearance that the flyback has failed when it hasn't. In the case of your 1084S though, flyback is a common failure. I'm not bashing your tech guys, and they might be great. But I'll just warn that I've also repaired monitors first looked at by other techs. I think the repair was too difficult for them so they claimed flyback failure and gave large repair esimates I guess in the hope that the customer would go away.
If possible have your techs replace EVERY electrolytic capacitor. After 20+ years, they are all bad or going bad and can cause a bad picture or a newly repaired monitor to fail again. They are not very expensive. The whole monitor can probably be done for $10-20US
One last item... I have seen monitors that have "leaky" picture tubes. (at least 2 of them were 1084's) The bad picture tube causes the flyback and high voltage circuit to be over worked, run hot and fail again soon. This is rare, but worth knowing if you get your monitor repaired and it dies again after a short time.
BTW, you can get a look at my most recent monitor repair here....
http://s544.photobucket.com/albums/hh331/PlazinJavelin/StarGate/Good luck
Plaz
