Yes, it's deliberately priced high because I consider it a niche app. Not many people who want it, but the people who do want it are willing to pay. But you might be right, I should also definitely consider lower prices.
I don't really see this as a niche app. A niche app to me is an app that a particular segment of the population would be actively searching for. For example, runners would be searching for a "run timing" app. I think your app falls into the mainstream simply because people (I don't think) are going to be actively searching for it. And when they do find it on the new releases list or some other method, there is no instant recognition as to what it does, so your price will drastically affect your conversion rate. That said, 3.99 I think is way too high. I think 99c may even be too high. I would start off free with ads with in-app-purchase option to remove them.
You might be right. I am tempted to make it 99 cents... however, I don't want to disappoint the people who just bought it. Feels a bit unfair to me... maybe in a few weeks.