Absolutely. I've had a contract where I could have done the job in two months; there were four people in the team and the contract was for six months. I spent most of my time reading articles on the internet :)

The reason for the over-budgeting? The team lead was a permanent employee trying to get promoted to manager; in order to do that, he needed a 1) successful and 2) significant project. Genuinely large projects risk being unsuccessful, but an overestimated one ticks both checkboxes.