Why is the OECD so afraid of formulary apportionment?

The OECD has been rolling out a very modest version of country-by-country reporting --only really, really big companies will have to report, the info must be kept strictly hidden from public view, the info mostly won't flow to the world's poorest jurisdictions--and now, from its Feb 6 report, I see that governments must use the info they obtain only to further arms' length transfer pricing, and not to try switching to formulary apportionment:

"Jurisdictions should not propose adjustments to the income of any taxpayer on the basis of an income allocation formula based on the data from the CbC Report"

Formulary apportionment must be a pretty effective way to tax multinationals at source, if the OECD is conditioning government-to-government data flows on not using it.

The picture I am drawing from the OECD's guidelines for CBC is very troubling. If I understand this correctly, the OECD wants info to flow from all jurisdictions to the ultimate parent jurisdiction, which will then dispense info to other jurisdictions provided they have tax information exchange agreements (TIEAs) with the parent jurisdiction, and provided they keep the secrets and don't use the information to switch to formulary apportionment, even if that is a better system for them than arm's length transfer pricing.

Since most multinationals are based in OECD countries, it starts to really matter which jurisdictions have TIEAs with these countries. Indeed, these TIEAs are starting to be the world's answer to everything tax cooperation-related. This means that a country without TIEAs is very quickly finding itself out in the cold when it comes to the brave new world of tax transparency being built by the USA and the OECD.

Just taking a quick zoom in to this world, it should be noted that the United States, home to many of the world's biggest and most profitable multinationals, has very few tax agreements with countries in Sub-Saharan Africa. It is not necessarily that these countries do not want tax agreements with the United States. Many of them have requested tax agreements for many years. But only the US decides who has a tax agreement with the US.

What does this mean for a country in Sub-Saharan Africa that is the destination for a US multinational's direct investment dollars? I am afraid it means that most will continue to struggle to impose income taxes on these multinationals. They will in effect be forced to continue using arm's length transfer pricing even if it is too expensive for them to administer effectively, and even if they would prefer to use formulary apportionment. Meanwhile, they will be forced to set up complex financial asset monitoring and reporting systems to ensure they are not locked out of the global financial system by the US via FATCA or the OECD via the common reporting standard.

Yet even after doing all of that, without the requisite tax agreements in place, these countries seem increasingly likely to receive no tax information from the US or the OECD. That leaves them virtually powerless to stop tax evasion by their own residents, who may freely continue to hide their financial assets in the United States and elsewhere. It also leaves them at a serious disadvantage in addressing complex tax avoidance by US and other OECD-based multinationals.

So much for that quaint notion of "tax sovereignty" the US and the OECD are always so worried about. And so much, I think, for the notion that developing countries have an effective voice in OECD decision-making. The OECD has been very clear that it did not want to even discuss formulary apportionment, even as it purported to review the fundamental international tax structure in its BEPS project. With this latest guidance, it seems the OECD is intent on building a framework that will eliminate any possibility for future discussion for formulary apportionment, as well.