The whole point of having employees is to have THEM do the work. At some point in time, the work gets massive enough that you have to hire additional PEs, who are then responsible for their individual subprojects. That's the nature of the business.
When management interferes, then there may, or may not, be something to deal with. What you're indicating is appears to be a difference of opinion, as opposed to a outright ethics breach. Unless there is quantifiable and documenttary evidence that your manageer's direction is unsafe, there is no ethical breach, per se.
Sometimes, this can occur because the bidder and the executor are different people, with different assumptions.
Otherwise, this is simply a problem you'll need to deal with. You can be ultraconservative, hence, unltraexpensive, and unemployed, or, you can be reasonably conservative, and gainfully employed.
But, unless you have specific proof of insufficient design, based on industry standards, then you're simply SOL.
TTFN