When you scout for players your money isn't deducted until the daily update, which happens at 16:00 server time. Basically you just enter the amount of money that you want to invest for the forthcoming day. For example, if I invest $10,000 today the money/investment wont update until 16:00 server time.
Am I wrong or did this answer your question?
Edit: Corrected 18:00 to 16:00.