Fantastische Hure said:
True, but Salza called the reading specifically "pathetic" (or something like that) IIRC. That seems like something which he just in-general doesn't think much of, yet Freeza praised someone who had a level of 42k.
Different characters have different standards for what they find commendable power. For instance, Goku still being impressed at the idea of someone who can oneshot Freeza being easily killed in the Boo Arc, whilst Vegeta viewed someone with decent implications of packing Freeza tier power like Pui Pui as a worthless opponent, or Dabura referring to Gohan as trash despite how close they were in power.
Freeza is also made apparent to have a feigned sense of politeness be one of his core character traits. He compliments Nail's power within the vacuum of Namekians which in his experience have capped out at 3k, yet later refers to Vegeta, Gohan and Kuririn as maggots and compares them to three ants fighting a dinosaur.
Sauzer's statement was in response to Dore's reading of Gohan having a battle power of 50 from having his tail grabbed and likely being suppressed to a resting level prior, so it's far from an accurate assessment. Dore also said prior to that "So this is a Super Saiyan?" suggesting he either believed Gohan to be Goku or expected him to be on the same level as his father.
Was it ever actually stated that he trained for the form? I know it makes sense since it's a transformed form from his normal state, but maybe he just got it as he got older naturally.
It's never stated, though there's no other real way he could gain an additional form without doing so (especially with the information revealed in Super for Freeza's GAINZ). It does fit in line with Coola's character though as the movie constantly presents him as being pragmatic in his actions and not wanting to make the mistakes of his brother; which when taking into account only Freeza and Cold are confirmed to be prodigies of their race in the Daizenshuu makes the necessity for Coola to require training to prove himself even more apparent.