I don't see why there'd be a downward sloping supply curve there. No matter how high initial costs / barriers to entry are, why would you ever want to produce more goods when the price lowers (or, in other words, require a lower price to be able to produce more goods)? The start-up costs are sunk costs and should be ignored in the decision making, right?
If the elasticity of demand is elastic, then a reduction in price will be made up for by the increased quantity that people buy. Use the total revenue test.