I find this a fascinating and relevant question. Thanks for asking! Disclaimer first: I work for AMF, but the opinion here is entirely my own. None of the content here is based on inside information or implies anything about the opinions of AMF; In fact, you could probably substitute AMF in my writing with any other effective charity.

Background: This 80000hours podcast episode with Phil @trammell makes a good case for being patient, i.e., investing your money and donating it later. I recommend listening to the episode. Yet I disagree with its conclusion and think that one should donate a significant portion of one's fund early. This post explains why.

Your presentation (if I understand it correctly) compares two scenarios:

1. Save your money for 10 years, then buy 3x as many bednets (wow that's 11.6% interest rate)
2. Buy the bednets now

I think option 2 will lead to more wellbeing overall. The main reason for this is that many interventions (including bednets) are better than cash. For bednets, GiveWell estimates a "cost-effectiveness in multiples of cash transfers" factor of 14-17.  To be clear: you get that boost in both scenarios. But in scenario 1, you get it now  and it will immediately start paying dividends. The effects are a stronger economy, better education, and others. Many of these will still be present after 10 years, and it seems highly plausible to me that the net benefit at that time exceeds 3x the price of the mosquito nets.

Let me end with some data to support my arguments:

• Fink and Masiye 2015: free ITNs increased the average annual harvest value for a farmer by $76, about 12% of the group’s average annual harvest value at baseline.
• Hamory et al 2020: Evaluated a deworming campaign 20 years after the intervention. "Given deworming's low cost, a conservative annualized social internal rate of return estimate is 37%."

I'd be really interested to hear other people's thoughts and arguments. This is a question that is important to me, both for work and personal reasons :)

Sjlver, you cited the article titled "Health and agricultural productivity: Evidence from Zambia." If I'm reading well, the randomized controlled trial measured about 10% to 15% increase in income during the next year for a population with free bednets.

That is a perfect example of the kinds of facts that I have been searching for. I welcome any more evidence.

Now I cited that exemplary article. In a spreadsheet cell.

Also, in the past few days I revised some estimates and sources of facts.

I ignorantly estimated of 3% to 5% compounding opportunity cost in annual productivity from malaria alone. This is based on a comment from Rob Mathers at a World Malaria Day presentation about the total economic opportunity cost of malaria per year divided by the income of an estimated population at risk of malaria. It is a crude estimate.

Phil's discussion had inspired the historical scenario of donating to AMF in 2010 or 2020. As can be seen in the crude estimates so far, I am currently uncertain. Therefore, I agree with you, Sjlver, that with such high uncertainty it seems to be a deadly gamble to delay a gift by 10 years.

Again anyone's comments on facts from 2010 to 2020 would inform an estimate of this historical scenario. If I can understand a simple historical scenario, then it would inform my giving plans for the future.