Need some suggestion on my SAAS App pricing.

Need some suggestion on my SAAS App pricing. I have a mobile SAAS app, http://dronebuddy.io It's in niche market, the app helps drone pilots pre-check the local wind weather info, and refer the no fly zone map which are critical for safety. The business model is free to download the app, if you want more info and data, you can subscribe to pro access. Right now I am charging $4.99/mo, $49.99/year, and also offer lifetime access at $99. It has around 680+ subscription in past 4 month now. I have listen many interview here at indie hacker, cortland always mentioned that you shouldn't charge a low price at $5 which is exactly what I did. I am thinking to charge $10/mo in the future, but scared that user will not pay for it. Come to pricing, it seems the size does matter, the bigger the screen, you higher the price, normally I can see people charge from $20 - $50 on a desktop app for just beginner. But mobile is kind different, it used to be $0.99 for the whole app. So it is normal the month fee be low on mobile devices than desktop app. Also should I offer lifetime subscription at all? Any feed back is appreciated!