architects disagree on necessity of civil engineering services...

[Chris Morris]

Architect A estimated I would need to pay $10K-$15K for civil engineering services for a 2 story ADU on a flat lot in Los Angeles.

They say it is for grading and low impact development/stormwater management).

Architect B thinks the civil engineering services could possibly be avoided entirely:

"Grading shouldnt be significant and not need design work.

FYI: Your property is in a special zone that requires extra hoops to jump through for grading, but I have only seen that triggered when excavating for a basement parking level. This would be an item that goes wrong, but is not anticipated.

LID/Stormwater can be covered by the architect/client with some simple notes and provisions for the project."

Any thoughts? Who is closer to the truth? 

Also, Architect B, if you see this post, no disrespect. I don't have experience in this area and am reaching out for more opinions. :-)