Realistically, you should only have 2 fields: downdatetime and updatetime.
The Date/Time data type is intended to represent a timestamp: under the
covers, it's an 8 byte floating point number where the integer portion
represents the date as the number of days relative to 30 Dec, 1899, and the
decimal portion represents the time as a fraction of a day. If you have a
need for only the date, or only the time, you can use the DateValue (or
TimeValue) function to extract it from the timestamp.
You can use the DateDiff function to calculate the difference between the
two:
DateDiff("n", [downdatetime], [updatetime])
(n is for minutes)
If you absolutely cannot combine the fields in your table, you can simply
add them together:
DateDiff("n", [downdate] + [downtime], [update] + [uptime])

Signature
Doug Steele, Microsoft Access MVP
http://I.Am/DougSteele
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> Hello,
>
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>
> Mary