My question involves employment and labor law for the state of: Texas

I am currently paid biweekly working Wednesday-Saturday night 12 hours shifts 6PM-6AM week1 and Wednesday-Friday night 12 hour shifts 6PM-6AM. No time is unpaid for lunch breaks, just a straight 12 hour shift.

Our work week ends on Saturday night/Sunday morning midnight. My week 1 shift runs right in the middle of these two weeks. Should this shift be split 6 hours into week 1 and 6 hours into week 2, resulting in two 42 hour work weeks, or should it be 48 hours worked in week 1 and 36 hours worked in week two? The difference being 4 hours of overtime is converted to regular time in the first scenario.

For what it's worth, if I were on day shift, I would be paid 48 hours week 1 and 36 hours week 2, essentially making less on night shift. When I was hired on, I was verbally informed that the pay would be 48 and 36, not 42 and 42. My boss confirms the verbal promise, however I have to deal with HR/payroll to change anything.

Thank you for the help ahead of time. Please let me know if you need any additional information.