Great job on this app's development! If I could purchase it once for $3 to $15 like most utilities and get all the advanced features permanently for the current app version, I would.
I'm betting your subscription-like model requires more financial commitment from potential customers than most people are willing to make for a utility app. That's the case for me. You could make a lot more $ from the many people like me who are out there if you'd offer a non-subscription purchase option at "the going rate" for utility apps. In a non-subscription-like payment system, you could still get ongoing income from past purchasers, if future upgrades are compelling enough to convince customers to buy new versions you release.
You may find out from others' responses to this post if this idea resonates with your audience.
Email me if you make a change like I've described, and I'll likely buy Time Out. With the current pricing model, I'll be looking at my other options for now.