Standard testing conditions for latent capacity?

I've just tested a A/C unit rated at 7kW net, with 75% sensible/25% latent split.

The spec sheet states 1.8kW latent. My acquired data shows its only getting me about half of this.

Evaporator side air is 25C, 40% RH
condensing temperature is also around 25C.

The system was allowed to run until water was coming out of drainage to "prime" it, then a container was placed under the drain and amount of water collected in an hour was measured. There is no condensate drain pump, so float timing is not an issue.

It collected 1.48kg. Assuming 2257kJ/kg heat of vaporization:

(2257kJ/kg*1.48kg)/3600 sec = 0.927kW

What does ASHRAE or ARI use for testing latent? Why is my measured latent as low as half of spec?