This is one cost they did put in their manifesto.
" On the NHS, the Tory manifesto says: "We will increase NHS spending by a minimum of £8 billion in real terms over the next five years, delivering an increase in real funding per head of the population for every year of the parliament."
What does this mean?
Does it mean what it says - £8bn of extra funding over five years, a mere pittance given the huge funding requirements of the service?
Does it mean what it might say - £8bn a year for five years, a significant commitment that would have a meaningful impact on the struggling NHS?
The manifesto certainly sounds like the former, and this is what the Tory press office said this morning. But then Conservative MP and potential post-election cabinet minister Dominic Raab told Andrew Neil on the BBC that it was £8bn each year - that means £40bn in total. Significant money.
The confusion was not limited to journalists - seasoned and respected health think tanks were working the phones, trying to decode the commitment as well.
In the end, Conservative press office has clarified that it's neither - it's not £8bn over five years, but it's not £8bn a year. It's £8bn more in the fifth year of the next parliament than now.
But what about the years in between?
We don't know. They don't know. The press office is trying to find out. But at this moment, there is absolutely no clarity on how much the Conservatives will spend on the NHS - it could be a little over £8bn over five years, or it could be just under £40bn over five years.
And we don't know where the money will come from. Partly because we don't know for sure whether this is simply recycling George Osborne's commitment made in 2015 to spend £8bn more by 2020, in which case, large chunks will not be new money.
So we have anywhere between £8bn and £40bn with no apparent costing."
Anyone understand it?