The perfect call seems to have convinced the president and his henchmen that Zelensky needed that extra incentive to do his bidding. He turned the screws that very night:

The Office of Management and Budget's first official action to withhold $250 million in Pentagon aid to Ukraine came on the evening of July 25, the same day President Donald Trump and Ukrainian President Volodymyr Zelensky spoke on the phone, according to a House Budget Committee summary of the office's documents.

That withholding letter, which was among documents provided to the committee, was signed by a career OMB official, the summary states. But the next month, OMB political appointee Michael Duffey signed letters taking over the decision to withhold both the Pentagon and State Department aid to Ukraine from the career official.

A hold was placed on the Ukraine aid at the beginning of July, and the agencies were notified at a July 18 meeting that it had been frozen at the direction of the White House, a week before the Trump-Zelensky call.

The career official who initially withheld the aid money was Mark Sandy, according to a source familiar with the matter.
The documents to the House Budget Committee provide additional insight into the actions going on inside the White House's budget office to hold up the US aid to Ukraine, a key part of the House Democrats' impeachment inquiry. The committee only received a partial production of documents, which are separate from the impeachment inquiry, and it's unclear what the significance is that the money was officially withheld on the same day as the July 25 call.

Sandy testified before House impeachment investigators in a closed-door deposition, while Duffey defied a subpoena.
OMB issued several short-term withholdings of the Ukraine aid in August and September. Some of the aid money was released September 11, the summary says, and the remainder of the funds were released on September 27 and September 30, which is the last day of the fiscal year.

The letters from Duffey show that on August 9, OMB said it would begin releasing 2% of the State Department funds each day, which the committee says prevented the normal spending of those funds.

Then on August 29, one day after Politico first reported that the aid had been withheld, Duffey signed another letter releasing 25% of the State Department funds each Sunday between September 1 and 22, according to the summary.
Asked about the information, an OMB spokesman said: "OMB has and will continue to use its apportionment authority to ensure taxpayer dollars are properly spent consistent with the President's priorities and with the law. This is the same old spin from Democrats."

They knew there was something wrong with it because they used their little loophole of releasing 2% which was technically compliant without actually releasing the funds.

I don't know that we've seen Sandy's transcript but it will be interesting to hear what they told him the reason was.

(Ed. Note: Mr. Sandy's transcript is here)

Posted with permission of Digby's Hullabaloo