The delay for iOS is due the the design for HTTP streaming.
The iOS device requires 3 chunks by default before it will play the stream hence the longer delay.
You can change values using the guide here,
Note : You are running a on demand application.
You can control the video on demand (VOD) chunk size by adding the following property to the HTTPStreamer/Properties container:
Try changing this value to 2000 and see if it help your streaming situation.