After days of confusion over Donald J. Trump’s hints that he would change his tax plan to reduce its budget-busting cost and make it less generous to the rich, his spokeswoman on Thursday sought to clear things up: He plans no changes, Hope Hicks said, and advisers who say otherwise do not speak for him.

One of those advisers, Stephen Moore of the Heritage Foundation, had his own response: “I’m a little bummed out if his spokeswoman says they’re not going to make any changes to the plan.”

Mr. Trump set off the speculation a week ago, shortly after becoming the presumptive Republican nominee for president, when he told the business cable network CNBC that his months-old tax plan was just a starting point for a final deal. As for his plan’s tilt toward the rich and corporations, Mr. Trump said, “I am not necessarily a huge fan of that,” adding, “I am so much more into the middle class, who have just been absolutely forgotten in our country.”…

Compounding the confusion, Politico reported on Wednesday that two informal advisers — Larry Kudlow, a CNBC host, and Mr. Moore, an economic commentator — said they were helping Mr. Trump at his request and had proposed changes to slash the plan’s cost from $10 trillion in its first decade to $3.8 trillion. They attributed the estimate to the conservative-leaning Tax Foundation.