If your costs were majority BTC and not fiat denominated, you probably wouldn't be lowering prices (yet).

Your costs to buy current inventory didn't change in BTC terms. Suppose you paid 1BTC to buy current inventory. Then, if the USD/BTC exchange rate doubled after your inventory purchase, you should not care. Your costs are still 1BTC and you should expect to make more than 1BTC in sales to make your effort worthwhile (profit). Because BTC is your unit of account.

If you refuse to lower prices in response to an exchange rate increase today, you will likely have much fewer sales. Since most of your customers are using USD unit of account. To them, the price has gone up even tho your costs are constant. Because you and the customer use different accounting units.

Just pointing out the flip-side of a dis-inflationary unit of account. It creates a disincentive to invest heavy in inventory, often this means forgoing the benefits of economies of scale. Makes supply chains less efficient.

As long as you are adjusting prices based on the exchange rate, your unit of account is still fiat-based. Don't fool yourself.