Take it easy. Could you maybe give us what is the exact driver? Also comment on how you got the voltage readings, multimeter? if so you should have the current aswell which would be the end of this mystery. the wattage you quoted is 229w, is that on the ac or dc side?
if its a HLG240-48x, datasheet says 5 amps output, 45V x 5 amps is 225 W. if the 229w is on the dc side then there is absolutely no anomaly. if its on the ac side then it seems your driver might be a few % under spec or measurement error. Again, you should check how much current it gives.
it might well be that your driver is a bit under spec which wouldnt surprise me. Unless you wanna send it back to china and argue with the supplier you might be stuck with it.
Never buy a driver from china unless you see it as disposable and unwarrantied. theyre pretty much the same price from digikey anyways.
Edit: sorry, i realize you posted the driver, 48b version on last page. Is there a dimmer? If so you can probably squeeze out more power by disconnecting it for full power.
229w Ac: something up, either in measurements or driver not outputting all 5A or being magicly efficient (like 100%)
On DC side: its normal, see dimmer advice above.
Hope it helps.