Always worth testing BUT not all places do accurate tests and charge too much.

If you are getting the car live mapped then it becomes less important
as the engine will be tested during mapping.

If using Dark Greens and if you are only aiming for 320 bhp and not more
then the injectors are not being worked too hard and any differences
become less critical.

Generally if using of the shelf chips, these will always have a "comfort zone"
where the tuner will deliberately add a small amount of fuel to get around
minor variants in fuel delivery.

Dont forget, its not just injectors that vary. Fuel pressure, engine
tolerances fuel quality etc.. all add up to induce minor fluctuations.