OK, make slight mod:
If previous({table.billid}) = {table.bill}
and
{table.status} <> "new" then
totext({table.datetime} - previous({table.datetime}),0,"")
else
"N/A"
This w2orks unless you want to ignore the case where the status did not change, such as your 3rd row in the example, in which case you'd use:
If previous({table.billid}) = {table.bill}
and
{table.newstatus} <> "new"
and
{table.oldstatus} <> {table.newstatus} then
totext(({table.datetime} - previous({table.datetime})),0,"")
else
"N/A"
-k