Points through current example
IG’s current GBP/USD price is 15349/15350, but the market is very volatile and you want to reduce your chance of getting a price rejection when you buy £100 per point.
You submit an order to buy £100 per point of GBP/USD up to 2 points through the current price. You are telling IG you are willing to pay up to 15352 (15350+2) to reduce your chance of a price rejection as you know the market is volatile. When IG receives your order our GBP/USD price has gone down 1 point to 15348/15349 and you get filled in £100 per point at 15349.