DSPS sleep systick

I am using the DSPS as the basis for my app, on a Basic DK board. I have set #define CFG_EXT_SLEEP. When I do my systick interrupt never fires, which it does if CFG_EXT_SLEEP is not defined. The unit continues to advertise, when it does not have a BLE connection.
my questions are
1. Is the unit going into ext_sleep mode between advertisements?
2. If so, what is waking it up?
3. What current consumption should I expect when it is in this mode (no BLE connection), with the J-Link disconnected?
4. If it is not in ext_sleep mode, how can I make it do so?