Hello Dywer,
this is a legitimate configuration
with default parameters every tracked interface down reduces the priority of 10
to switch to the other router
the other router must have preemption enabled and also this to be able to regain role when link is restored
on both routers:
int vlan15
standby 10 preempt
it is your choice how many links have to be down before switchover
if standby has priority 95 just one is enough if it has 85 two links must be down
first case:
100 -10 = 90 < 95 -> switchover
100 -10 = 90 > 85 -> no switchover
a second tracked link is down
100 -10 -10 = 80 < 85 -> switchover
Hope to help
Giuseppe