I had to do a little digging to respond to this properly.
I was on the "Pro Trial" where you get 150 premium requests and I had very quickly used 34 for them, which admittedly is 22% and not 30%. Their pricing page says that the Free plan includes "Pro two-week trial", but they do not explain that on the pro trial you only get 150 premium requests and that on the real Pro plan you get 500 premium requests. So you're correct to be skeptical, I did not use 30% of 500 requests on the Pro plan. I used 22% of the 150 requests you get on the Trial Pro plan.
And yes, I think the agent mode can burn through credits pretty quickly.
I was on the "Pro Trial" where you get 150 premium requests and I had very quickly used 34 for them, which admittedly is 22% and not 30%. Their pricing page says that the Free plan includes "Pro two-week trial", but they do not explain that on the pro trial you only get 150 premium requests and that on the real Pro plan you get 500 premium requests. So you're correct to be skeptical, I did not use 30% of 500 requests on the Pro plan. I used 22% of the 150 requests you get on the Trial Pro plan.
And yes, I think the agent mode can burn through credits pretty quickly.