Jim,
None of the ballistic programs I use (mostly JBM's website (You need to Login or Register to view media files and links)) will show a 100 of no wind followed by 100 yds of crosswind, or vise versa.

If you simply compare winddrift at 100 vs 200 with a crosswind the whole way, you simply have the composite effect of wind over the entire distance.  The programs are useless for telling you what to do when wind is variable over the path of the bullet.   

Brent

Okay okay.   

Joe's point is that the bullet, as it crosses the 100 yd mark is moving sideways because of the wind that has already experienced.  Let's take a stab about how fast it is moving in that direction.  I don't have a time of flight for your bullet at each distance, but let's just call it 1 arbitrary Unit.  We could call it a Borton just for fun

So, when the bullet left the muzzle, it was traveling 0 inches per Borton sideways.  But by the time it got to 100 yds it had moved 2.27" sideways in that one Borton.  Roughly we can approximate the sideways increase in velocity as linear - because I'm lazy and say that for the bullet to make it this far sideways, given that it was going 0 inches per Borton sideways when it left the muzzle it must be going about 2 times 2.27" or 4.52 inches per Borton sideways.   

If there is not no wind at all over the last 100 yds, the bullet will continue loafing along sideways because there is nothing to stop it.  Its sideways motion will slow a little, but not much over the remaining Borton time units to 200.  So, let's ignore that just for the heck of it and assume that the bullet continues down range at the same speed that it flew over the first 100 yds (again because it is easy).   

What you get is that for the next Borton, the bullet will move another 4.52" further sideways even if there is NO WIND over the last 100 yds. The result is that the wind over the first 100 yd will have pushed the bullet 2.27+4.52"= 6.79" to the side.  There is some round off error, but assuming that the bullet does not slow sideways is somewhat canceled by also assuming that it's downrange velocity does not slow also, so we are more or less ballpark.   

And 6.79 is the majority of 9.24". 

Just remember, you asked for the math...

Brent