> they account for social service transfers
They claim to account for them. Whether they actually did so in any way that makes sense is not documented. Given the credibility of the source... ¯\_(ツ)_/¯
Also, their claim is "social benefits paid to households". That wording strongly suggests that they only took into account those social benefits that result in a payment, of money, from the government to the households, such as social security payments or unemployment benefits.
Which would miss the vast majority of benefits, including all the ones I mentioned, because those benefits don't work that way.