Employee End Date with WORKDAY.INTL() function using Hire Date

How can I adjust/manipulate the WORKDAY. INTL() function so that it accepts the HIRE DATE instead of the first WORK DATE and still return the correct end date?

For example -

Employee is working a Saturday/Sunday ONLY schedule with no holidays. Start day is 4/14/18 (Saturday) and they are scheduled to work for 5 full work days.

In this case,

A1 = 4/14/18
A2 = 5
A3 = =WORKDAY.INTL(A1,A2-1,"1111100")

That will correctly return 4/28/18 as the last day the employee will be working.

However, if I put A1 as a day that does not fall on a Sat/Sun, e.g. A1 = 4/13/18 (Friday), A3 will spit out 4/22/18 which is incorrect. Putting in 4/9 to 4/12 (Monday to Thursday) all returns the same result.

How can I have WORKDAY.INTL ignore the days before the first actual workday?

Thanks!