How many records are deleted by this command?

>Actually this is what I see:
>
>Open 1st instance of VFP
>Execute DELETE - runs fast
>
>Open 2nd instance of VFP
>USE the 2 tables
>
>Back into the 1st instance
>Execute DELETE - slow
>
>Close the 2nd
>In the 1st run DELETE - slow !!!
>Reopen tables
>Run Delete again - fast
>
>What's going on?