Can you test Mod(<number>, 1000) to make round
Mod(2140, 500) = 140 > Down (<number>  140)
Mod(2257, 500) = 257 > Up (simply <number>  257 + 500)
Mod(2660, 500) = 160 > Down (<number>  160)
Mod(2760, 500) = 260 > Up (2760  260 + 500)
and so on...
