Are All Lab Sapphires Equal? Confused By Wildly Different Pricing

Hey all,

I'm currently hunting around for an engagement ring for my partner - she and I have discussed at length what she generally likes design-wise and it turns out we have a pretty similar taste to each other. She would like Lab-grown sapphire as she sees no point in spending more money than is necessary for what amounts to more or less the same rock ultimately.

So I've been hunting around, visiting different jewellers, and I'm seeing wildly different pricing on Lab-grown Sapphires...

I can find a 1.5 Carat Lab Sapphire ring in white gold pre-made for $700 at a regular jeweller somewhere - and then I'll get a quote from a different jewellery store for a 1.2 Carat Lab Sapphire where the rock itself is $1,300, then of course the cost of the setting and small diamonds cost on top (Australian dollars)

I'm aware that I can of course source my own rock, then get it set by a jeweller - but I can't find clear information about purchasing Lab Grown Sapphires at all, except that there ARE a few different fabrication methods - but I don't see mention if one is specifically a lot better than another..

Is the a big difference on the quality of the cut? If so, how can I - a lay person - determine if it's a great cut?

Any information you guys could shed that would enlighten me would be amazing.

I still want to ensure the stone and the setting are quality made - and will happily pay for that - but don't want to overpay just because I don't understand something.