Thanks for checking again. A few corrections first.

1. An Ancient Pine pays 0.144 HIVE per watering (0.09 base × 1.6 at Ancient), not 0.27. That 0.27 comes from the old growth curve.

2. Golden Nectar changed the same day: a bonus with Nectar now pays 3x instead of 2.5x.

3. Two of the sums are off: 0.27 + 10% of 0.27 is 0.297, not 0.287, and 0.351 − 0.20 is 0.151, not 0.178.

With the current numbers, on an Ancient Pine:

• No boost: 10% chance, 2x, 0.158 HIVE on average
• Pollen only: 20%, 2x, 0.173 (+0.014 for 0.08)
• Nectar only: 10%, 3x, 0.173 (+0.014 for 0.12)
• Both: 20%, 3x, 0.202 (+0.043 for 0.20)

So your conclusion is right, and it's by design. No boost pays back its price on average. A boost is a bet on a bigger watering, plus a season point for each unit you buy. Nothing in the shop is meant to beat a plain watering in HIVE. If it did, the game would be paying people to buy items until the reward pool ran dry. If you want the best HIVE return, the answer is simple: don't use boosts.

You don't need to do this by hand. Tap the ℹ next to "Bonus chance" in any tree's panel. It shows that tree's exact odds and average payout with and without each boost.

Boosts will stay priced above what they return on average.