if your worrying about $300 this early in your build, you have a LONG WAY to go before you get to the end. Instead of looking at the 'wasted' $300, look at how much your probably saving by hiring out the pumping yourself, setting the ICFs, and all the other parts involved in the foundation.
$300 is 2.5 yards of concrete. if you try to rush it and its not set enough, and you have a blowout from the pressure, there goes 5-10-15 yds of concrete, however many ICF forms you have to replace (which you wont have on hand) so there is additional cutting, demo, resetting, etc time that is many many thousands of dollars of cost.
sure you can use conveyor trucks, IF a fully loaded cement truck can even drive remotely close to your foundation, ON ALL SIDES, and still be above the top of the forms. many new houses around here are 3-5-7' above ground when the forms are set, which is well above chute or conveyor height. plus septic, if applicable, often limits where the truck can drive as well.
like shown above pumping over the house, pump trucks put thousands and thousands of lbs of material exactly where its needed with no extra work. when we poured the forms for my basement (400' of 11' wall total) the top of the forms were 8' above existing grade, so we definitely needed a pump truck. we had a septic in the whole front, a pool excavated in the back, so access was very limited. we had a 50m pump truck and used every bit of it to reach the back corner of the foundation 130' from where the truck was parked. it took two guys to pull the hose end out enough to make it into the top of the forms in that corner.
3 years ago, a pump was $995/4hr minimum and $5/yd. it allowed my foundation company to pump almost 1400 yds in just over 5 hours.