Honestly, I don't trust any company claiming that their product will provide a workaround for PCI compliance, unless part of the sales contract states that they'll pay part of the fines if you fail an audit do to that product not being sufficient. I would at least consult a 3rd party scanning/auditing company to get their opinion on it. After all, they and their kind be the ones putting the screws to you if you get audited. I've gone through, and passed, two PCI audits so far; one was just a scramble to provide data to AMEX, the other a full blown, forensic audit. It's a miserable, miserable experience, even with knowing that all of my POS hardware/software is within compliancy. I'd never want to do that with an "is it enough" question in the back of my mind.
That's probably all a moot point anyway; MerchantLink will not generate codes for a Micros system out of compliancy. Res 4.6 is out of compliancy. It's allowed for existing systems, but not for new installations/openings. You have to be on at least Res 4.11. However, as someone said above, after mid-April the XP server will put you out of compliancy regardless of the version of Micros you're running so you won't be able to get the credit card drivers configured.
I'm a little confused about your workstations, are they Eclipses, or Win CE (WS4 or LX). Eclipses run XP and will be non-compliant. WS4's use CE4 and will expire in 2015, LX workstations run CE6 and are still good for a few years.