Hi @Dean_Harris - you could calculate an “effective start date” based on whether or not the start time was after midday:
using the formula:
DATETIME_PARSE(
IF(
VALUE(DATETIME_FORMAT(Start, 'H')) >= 12,
DATETIME_FORMAT(DATEADD(Start, 1, 'day'), 'DD/MM/YYYY'),
DATETIME_FORMAT(Start, 'DD/MM/YYYY')
),
'DD/MM/YYYY'
)
Then use this new date in your WORKDAY formula.