If you offer 'free' postage then you will (and always have) pay fees on the postage component.

If you offer free pickup on a flat rate or calculated postage cost which is shown separately in your listing, then I have no idea as to whether the seller will be charged on the nonexistant postage component. We are all waiting for clarification on that point. But your seller who has shifted to 'free' post only has made a presumptive decision (led no doubt by eBay's insistence that 'best' match has any meaning) to pay the extra whether or not they post. And presumably won't be offering discounts for pickup. Or combined on multiple items, as that cannot be done when using 'free' post.