Tested on an Issue 1 and Issue 2 Spectrum +3.
Multiple purchases will be combined to give the best possible shipping costs. The website engine will try to calculate this, but often, because of the way both size and weight and number of units purchased can effect the cost, the price given may be too high. We always review the final package and can often get a better cost on the day.
If this is the case we will send a PayPal refund after dispatch.