When I play terran, thats usually my mistake when I lose to all ins. bunkers with repair are very strong by themselves. It only takes a little extra to completely cock block their all ins

use your 3rd set of 50 energy on your orbital to scan. (you build it, then use a mule, wait for 50 mule, wait for 50 scan the main)

5 minutes, 7 and 10 are the critical scanning times too if I recall. I might actually be wrong on that though