Update the other columns which are for to have minimum of other 2 columns , difference between 2 columns , and others
update t set
 min_count = least(count_s, count_t),
 diff = count_s - count_t,
 negative_diff = decode(sign(count_s - count_t), -1, count_s - count_t, 0),
 positive_diff = decode(sign(count_s - count_t),  1, count_s - count_t, 0)
;


Or just use virtual columns since you are on 11g:

create table t(
  subscriber_id number, 
  count_s number, 
  count_t number, 
  min_count as (least(count_s, count_t)),
  diff as (count_s - count_t), 
  negative_diff as (decode(sign(count_s - count_t), -1, count_s - count_t, 0)), 
  positive_diff as (decode(sign(count_s - count_t),  1, count_s - count_t, 0))
);