eBay will not calculate postage discounts

I run an eBay Anchor store on a different ID and offer flat rate postage with a discount for multiple purchases. It has been this way for over a year now and postage has always been calculated correctly during the checkout process. I allow the buyer to self checkout and pay. The product I sell are stamps, so weight or size is never an issue. Around 3-4 days ago the ebay system stopped automatically calculating postage discounts and simply multiplied my standard rate by the number of items. I have changed nothing, the discounts still show in my postage/shipping preferences. There is no reason that I can see, why my customers should not still automatically get postage discounts from me. Very frustrating. Is anyone else having the same problem? Is there a simple solution that does not involve making manual adjustments to over 2500 items. Due to the situation in the Philipines I am unable to currently get a response from eBay (which is fair enough while they make alternative arrangements). All practical help or moral support greatly appreciated...cheers Jezza