When XL Visual purchases the LEDs, we have strict requirements for the wavelengths of the LED. We will do chroma calibration and compare with reference tiles, to make sure each batch performs as expected. If you want to buy more LED panels, this is best done form the same batch for that reason. We do keep an administration of this for our customers convenience, but cannot always guarantee to have that particular batch available. If the panels you have are a bit older and used a lot, it is possible that the LED's have aged. In that case it would be better to customize the calibration to match your existing panels.