Need help to understand Redshift Serverless costs

I'm using Redshift Serverless to run some tests, but I don't understand how it's being billed. I'm still on the Free Tier $300, but already used almost $50 of those, and according to my calculations, the cost should be less than $2 so far.

I understand that Redshift Serverless is billed for RPU and Storage. But when I check the usage using:

select
  date_trunc('day', start_time) usage_date,
  sum(compute_seconds) total_compute_seconds,
  sum(compute_seconds)/(60*60) total_compute_hours,
  total_compute_hours*0.375 total_compute_cost
from sys_serverless_usage
group by date_trunc('day', start_time);

Result shows that the cost should be less than $2 so far:

Storage doesn't seem to be the cost either, as the cost of it shows $0 so far, using:

SELECT date_trunc('day', start_time) usage_date,
SUM((data_storage/(1024*1024*1024))*(datediff(s,start_time,end_time)/3600.0)) AS GB_hours,
GB_hours / 720 AS GB_months,
GB_months*0.024 AS storage_cost_day
FROM sys_serverless_usage
GROUP BY 1 ORDER BY 1;

I need help to understand where the money is going, if there is some fixed cost or how is it draining so fast?

I also tried to find Redshift Serverless on the Billing section, but it doesn't seem to be there (maybe cause it's still under the Free Tier, but some services show up there even when cost is $0)

Thanks in advance!