WASHINGTON (Reuters) - The Republican tax bill being debated in the U.S. House of Representatives would add $1.7 trillion to the federal budget deficit over 10 years, when recent changes put forth by the head of its tax-writing panel and estimated debt service costs are included, the nonpartisan Congressional Budget Office said. “By CBO’s estimate, additional debt service would boost the 10-year increase in deficits to $1.7 trillion,” the office said in a letter on Wednesday to Representative Richard Neal, the top Democrat on the tax-writing House Ways and Means Committee. 