There isn't a way to format seconds with decimal points (and even if you
could, it may not be as accurate as you'd like, given how times are stored).
My suggestion would be to store your times as Long Integers representing
hundreds of seconds. In other words, for 1:14.24, store 7424. Write your own
functions to translated from HundredsOfSeconds to m:ss.dd and from m:ss.dd
to HundredsOfSeconds.
For example, the following untested air-code should convert from
HundredsOfSeconds to m:ss.dd
Function FormatTime(HundredsOfSeconds As Long) As String
Dim lngMinutes As Long
Dim lngSeconds As Long
Dim lngRemainder As Long
lngSeconds = HundredsOfSeconds \ 100
lngRemainder = HundredsOfSeconds - (100 * lngSeconds)
lngMinutes = lngSeconds \ 60
lngSeconds = lngSeconds - (60 * lngMinutes)
FormatTime = Format$(lngMinutes, "0") & ":" & _
Format$(lngSeconds, "00") & "." & _
Format$(lngRemainder, "00")
End Function