Hong Kong, Taiwan, and the Mainland all write in Standard Written Chinese. Hong Kongers do not expect to see Cantonese in materials translated from a foreign original, and largely do not want to. HK/TW/CN have a few vocabulary differences (e.g. "taxi" is HK's "dishi", TW's "jichengche", and CN's "chuzuche"). Orthogonal to the vocabulary differences, HK and TW use Traditional characters, SG and ZH use Simplified. But I can write "chuzuche" in Traditional, or "jichengche" in Simplified. They still mean the same thing and are still understandable to all.
While we hope to offer translations into Traditional Chinese by Cantonese speakers in the future, currently our translations are not ideal if you hope to sell your product in Hong Kong.
Traditional to Simplified mapping is perfectly surjective. That is to say, it can be done by computer with 100% accuracy. Having a Traditional Chinese and a Simplified Chinese version of a document does NOT require two separate translations from the source document, as you seem to be implying.
Let me draw an analogy, Britain says "boot" and "bonnet" and "bobby" where America says "trunk" and "hood" and "cop". That does not mean everyone needs to get separate British English and American English translations, nor separate Taiwan Chinese and Singapore Chinese translations. In one extreme, if I were a high volume group-buying website looking to expand globally, yes of course I want the whole interface and the terms and conditions done up separately for each English and for each Chinese. In the other extreme, if I ran a boutique hotel and just wanted to give my Chinese customers directions from the airport to my doorstep, I have no need for separate translations.
In between is a giant grey area where full-service Language Service Providers generally try to provide some guidance to their clients. As a low-cost LSP maybe you are not aiming at the kind of client who needs this kind of guidance --- in which case you shouldn't be purporting to offer it. You should define yourself clearly.