My husband (let's get an engineer in here to really foul things up) says we were 4 hours different and when we change we'll be 3 hours different.

Boston's 10:00 daylight savings is Phoenix's 6 o'clock and Boston's 9:00 Eastern standard is Phoenix's 6 o'clock.

Boston's 11:00 daylight savings is Phoenix's 7 o'clock and
Boston's 10:00 Eastern standard is Phoenix's 7 o'clock

Boston's 9:00 daylight savings is Phoenix's 5 o'clock and
Boston's 8:00 Eastern standard is Phoenix's 5 o'clock