It is possible since Wah Chan sells diamond at quite a fair price. But then, we still have to see what kind of service (able to educate customers, get diamond images, etc) and diamonds Frou Frou is able to provide.

You probably need to compare the diamonds' 4Cs and proportions that they offer, along with the prices to make the final decision. I can't say which is better, but most people then went to Wah Chan seems to be pretty satisfied with it. You can FB both of them and see what they have in-stores for you. I think (no guarantee) both also have WhatsApp number that you can contact as well. Just google it.

Good luck.