a) There were actually 175 enrollees (per the 10K)
b) You look like you used something less than an R^2 enrollment curve (which is optimistic since it has patients enrolling earlier). A more normal enrollment pattern is r^2. However I used r^4 as a conservative assumption since GTOP, for instance, enrolled 40% of their patients in the last 6 months of 36 months. r^4 is a little more conservative than even GTOP.