Not really.
According to the Daizenshuu books, the elder Kaioshin's ability is described as drawing out dormant power beyond its limits, but Goku did mention in the manga he was impressed by the amount of dormant power Gohan had (I believe that was when Gohan released a part of it).
You just made my point with that link, the patriarch namekian brought already the hidden potential sort of speak, the elders ritual went far above that
While i do agree Goku was surprised, he could have could have been just as surprised by his own results or vegetas have they went to go with that ritual
From the source material:
[spoiler]Here he brags about his special ability like i said in previous posts (did this as well on the anime)
here he explains how it works, allowing him to draw latent power from even the most skilled fighter, and then points out that if gohan was able to master swinging the z sword, he would be the strongest when he is done with him just based on that fact. (goku could swing it as well and there is nothing to believe vegeta wouldn't be able to master the sword either)

[/spoiler]
Then, there is no contradiction. He didn't say anything overwriting what was in the Daizenshuu books in this case.
But he didn't confirm it either, this would have been the perfect time to lay that info if he felt it was relevant but he didn't. I dont place much value on magazines and other promotional material content unless that content is straight from the creators in which i case i will shut up
But ok fair point, still doesn't explain why Trunks turn SS faster than Future trunks, well there is... and that is plot requirement/context saga etc.
For argument sake lets say this is a fact, it does not contradict what i said about saiyans and hybrids having the same potential, whats more i conceded the advantage of them hybrids being born with higher base power
Despite Vegeta being naturally more gifted than Goku, he lacks his guts. Goku also knows better how to handle the amount of workout he needs to get the best of his body and mind. Vegeta doesn't relax when he needs.
Thats good, but why else? goku also always manages to put hail Marys in battle, why do you think that is? (you know what is the answer I'm inducing you to say right? just to make a point

)
Also i wouldn't say Vegeta is more gifted than Goku, quite the
opposite actually vegeta even said so as much he recognized him for the genius he is in battle and his natural talent
You will have to define what same "time frame and circumstances" are. A year in a hostil environment granted different results for the four Saiyans. Gohan got the best result because he had Goku as a sparring partner and Goku succeeded in bringing out his dormant power. Goku had the second best, because he sparred with his gifted son. Vegeta the third best, because he trained alone, despite being naturally more gifted than Goku. Trunks had pratically the same result as Vegeta because he trained alone and doesn't have the same battle experience as Goku and Vegeta.
What i mean by that is same amount of training, time training, same context (i.e saga), most important of all barring plot requirements (i.e gohan/goku being the hero)
See how out out of 4 saiyans 3 progressed the same considering their circumstances (no sparring for trunks and vegeta) and the plot requirement for goku to pass the torch to Gohan. Vegeta and trunks is the perfect example of saiyans and hybrids progressing similarly under similar circumstances
There is no telling how strong he would get if Goku was his partner in the room, which I believe would be the best for him.
or how strong would goku be if he was determined to be the strongest and not passing the torch