Auto-renewing subscription question

After developing a number of "paid up front" apps, I've just released my first subscription-based app. I set it up with monthly and annual options, both with a 30-day free trial as a promo. Unfortunately about 2 out of 3 users who install it don't use it at all. Based on support questions, I've determined that the App Store listing of "Free" with "In-app purchases" leads to an expectation that they can begin using it immediately for a month. When hit with a paywall on launch, they bail, without reading the "Free trial starts with choosing a plan" header. This being my first app with IAP, I had 3 rejections before I finally got it through review. I want to change the promo end date from "No end" to a date at which time I will release a new build that takes them straight into the app instead of the paywall. For you App Store veterans, am I setting myself up for a bag of hurt? Is it legal to change the date on a promo? Will the review gods smite me? Thanks for your input!
Auto-renewing subscription question
 
 
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