Calculating colipase activity How to Calculate Colipase activity using titration method pH$8$

Titrent Concentrstion $0\mathrm{.}02$N NaOH

Change Rate $($ml$/$min$)0\mathrm{.}085$

Stock soluton activity $14000$U$/$ml

I made working stoock of $1400$u$/$ml

Amount of sample used $75$uL

Total volume of Assay $($Buffer $+$substrate $15$ml

Calculate activity I used the following $=($Rate $($ml$/$min$)*$ Titrant Concnetration $)*$Df

volume of enzyme $75$ul

When I calculate antivity is only ~$3000$U$/$ml am I calculating this correctly please show your steps