This is the first sign the show gives for saying no to a deal: during discovery, the scope of the engagement starts to creep because of the prospect. Extra demands, extra features, revisions, something custom, and no intention of paying for it.
Price the extras, in writing, now. The response tells you which deal you are in. The behaviour is diagnostic precisely because it is happening before close, when they are on their best behaviour.
Do not absorb it to protect the close. The people who pay for that are the delivery team, who inherit the scope, and finance, who inherit the margin.
Source: When to Say No to a Deal and Toxic Customers, episode 102 of the Oil & Gas Sales & Marketing Podcast.
The next step
If the way energy buyers actually buy is costing you deals, talk it through with ModalPoint, the go-to-market firm Matthew Bertram runs. A 30-minute discovery call: no scope, no commitment, and a mutual NDA before anything substantive. You get a reply within one business day, and the first call is with someone who works in the sector.