I asked for a table comparing numbers from a screenshot from your 2021 analysis (linked above from @Abs_max ) with the GTP numbers.
| Country | Region | Weight PI | Weight GTP | PI US | GTP US | PI IE | GTP IE |
|---|---|---|---|---|---|---|---|
| United States | US | 60.1 | 58.0 | 0.0 | 0.0 | 15.0 | 15.0 |
| Japan | Japan | 5.8 | 6.2 | 10.0 | 10.0 | 15.0 | 15.0 |
| China (mainland) | Emerging markets | 4.0 | 4.0 | 10.0 | 10.0 | 10.0 | 10.0 |
| United Kingdom | Developed Europe | 3.7 | 3.8 | 0.0 | 0.0 | 0.0 | 0.0 |
| Canada | Canada | 2.9 | 3.2 | 15.0 | 15.0 | 25.0 | 25.0 |
| France | Developed Europe | 2.9 | 3.1 | 15.0 | 15.0 | 3.0 | 15.0 |
| Switzerland | Developed Europe | 2.6 | 2.8 | 17.5 | 15.0 | 35.0 | 15.0 |
| Germany | Developed Europe | 2.4 | 2.6 | 12.0 | 15.0 | 12.8 | 15.0 |
| Australia | Asia-Pacific ex Japan | 1.8 | 2.1 | 0.0 | 0.0 | 0.0 | 15.0 |
| Taiwan | Emerging markets | 1.7 | 1.8 | 20.0 | 21.0 | 20.0 | 21.0 |
| South Korea | Emerging markets | 1.5 | 1.6 | 17.6 | 22.0 | 22.0 | 22.0 |
| India | Emerging markets | 1.3 | 1.4 | 7.5 | 25.0 | 5.0 | 10.0 |
| Netherlands | Developed Europe | 1.3 | 1.1 | 15.0 | 15.0 | 13.0 | 15.0 |
| Sweden | Developed Europe | 1.0 | 0.9 | 8.4 | 15.0 | 3.0 | 15.0 |
| Hong Kong | Asia-Pacific ex Japan | 0.8 | 0.8 | 0.0 | 0.0 | 0.0 | 0.0 |
| Denmark | Developed Europe | 0.7 | 0.7 | 15.0 | 15.0 | 15.0 | 15.0 |
| Spain | Developed Europe | 0.6 | 0.6 | 15.0 | 15.0 | 15.0 | 15.0 |
| Italy | Developed Europe | 0.6 | 0.5 | 15.0 | 15.0 | 16.0 | 15.0 |
| Brazil | Emerging markets | 0.5 | 0.4 | 8.2 | 15.0 | 13.0 | 15.0 |
Let’s ignore the weighting, might be timing or index used and it’s close enough. Could you comment e.g. the 3% for France with IE-domicile, or 17.5% for Switzerland with US domicile? I did find the 15% in the DTA, but haven’t read the fine-print.
Here’s the cheeky GTP answer, not mine 
France
- France-US DTA: Typically, the withholding tax on dividends paid from France to the US is 15%【source: US-France Tax Treaty】.
- France-Ireland DTA: Typically, the withholding tax on dividends paid from France to Ireland is 15%【source: Ireland-France Tax Treaty】.
The 3% figure for PI IE seems unusual and incorrect.
The GTP rates seem to be more accurate based on the double tax agreements and authoritative sources. The discrepancies in the PI rates might be due to incorrect assumptions or outdated information.