Using Sleep command

[suded]

Hello again,
Can I ask once more about Sleep command.
I'm running it OK on 16F84.
When using 18F1220 I get 1/4 of the delay value.
On the 16F84 the delay depends on processor voltage but more or less close.
Usually 12 seconds more for each minute of delay but consistent.
Do I need to set any registers on the 18F1220.
Any one please.