That's really useful Xinhuan, thanks. I'm playing around with 0.5^1/8 etc

assuming n=8 to simplify things for selecting targets, it gets really easy

after 1 hour, DR = 0.5^0.125 = 0.917

here is my table that I typed out in OneNote:

DR= 0.5^0.125=0.917 1 hour x/n=1/8
.5^.25=0.8409 2 hours x/n=2/8
.5^.375=0.7711 3 hours
.5^.5=0.7071 4 hrs
.5^.625=0.6484 5 hrs
.5^.75=0.5946 6hrs
.5^.875=0.5453 7 hrs
.5^1=0.5 8 hours x/n=1

Then we just add all the DR's up for multiple hits.

(PS And I don't know about you , but I had to look up the ^ (caret) symbol to confirm that it means "to the power of". And if you want to calculate this exactly using Windows calculator you'll have to use the scientific view)