Hi Frederico,
The get pricing endpoint will always return the maximum possible price for any given job, this also assumes the most expensive transportation type in this estimation. As detailed in this post here, smaller transportation types may result in a price that is less than the quote.
Whilst you are able to specify transportation type, with it being a required field in France, we do not usually recommend specifying it in the UK and Spanish regions where package type is specified, as this may restrict how many couriers are available for your jobs, depending on your area.
May I ask which countries you plan to operate in? As this may also affect which transport types would also be available.
You can have full confidence that the price will not exceed the quoted price from the get pricing endpoint however.
I hope this helps.
Kind regards,
Henry