Quote Originally Posted by Marcol
All three methods seem to return the same result if the "string" has 5 or more characters (I tested up to1993428)
Not so.

Format the result cells as per earlier posts: [hh]:mm:ss (or General/Number)

You will find that TIME related functions only ever relate to the decimal remainder (integer is ignored).

The TEXT method with manual coercion (ie 0+ rather than use of TIME related function) will return the cumulative time - ie inclusive of complete days.