Mixing subscription and one-off purchase events in ROAS campaigns can silently hurt LTV

A digital marketer discovered that blending subscription checkouts and one-off purchases into a single Purchase conversion event caused subscription attach rates to collapse from 40% to under 12% over several weeks. Because one-off buyers were cheaper and more plentiful, the ad platform's algorithm naturally optimized toward them, ignoring the significantly higher lifetime value of subscribers. The fix required separating campaigns entirely — two distinct conversion actions and campaign containers on both Meta and Google PMax — rather than adjusting settings within a single campaign. To make bid separation effective, the marketer replaced checkout revenue with projected 6-month LTV as the conversion signal for subscription events, passed via a Cloudflare Workers webhook. The author notes this approach only justifies the added complexity when subscription LTV exceeds roughly 2.5 times the one-off average order value.