[tor-relays] uptime "algorithm"

[Dr. Who]

As far as understand it is the flag HSdir given to nodes with a fast
enough connection and a long enough uptime.

If I keep my tor relay version always up to the current stable version I
sometimes do have to restart the process. So I get a drop in my uptime
and loose the HSdir flag for several days.
Other nodes who don't care about versions keep the flag, despite the
fact they might use older/inefficient/insecure/buggy versions.

Wouldn't it be better to monitor the reason for a drop in uptime? In
case at the same time a restart occurs the version increases it might be
given the HSdir flag again?

someone understands what I mean?