You're right. Reagan had to agree to spending increases in order to get the Dems to pass his programs, including tax cuts.
And while the tax cuts soon resulted in increased revenue to the Treasury, the increased spending still caused a deficit.
The lying Dems have claimed ever since that the Reagan tax cuts caused the deficits.
You're wrong. That was not true in Reagan's first three years in office, which is what this debate is all about. There are mandatory expenditures and discretionary expenditures. Mandatory expenditures can't be touched without Congress changing statutory law through newly enacted legislation. When you take Reagan's defense increases off the table, what's left are all non-mandatory spending on individual departments.
The CATO analysis from August 2003, specifcally indicates PresReagan reduced non-military discretionary spending by 13.5% in his first three years in office. PresBush has increased that same discretionary spending by 20.8%.