Tesla will not work as hard as other smaller installations to do things out of the box, or difficult. They are looking to fill the area under the curve, so if your job is being too difficult, they can sell those Powerwalls elsewhere easily.
It sounds like the plan checker who checked your plans was different than the one that checked Tesla plans. They didn't give the same comments, so the installation has different requirements. Also your neighbors house may be at a different elevation or location due to level of danger in the floodplain.
The inspectors are also not the plan checkers and typically have different skill sets. You would have limited success talking to one about why you have a flood issue and your neighbor does not. It might negatively affect your neighbors installation.
Also, if you have 2 or more PW and your neighbor just one, there is sometimes a different review process for 20 kWh and more, vs under that limit.
Our company is dealing with this currently with County of Santa Clara. They are requiring us to put them 48" above grade, or prove that the floodwaters are lower than that with an engineer.
Thanks for the advice. I'm also in Santa Clara County. My neighbor's house is right next to mine so we are definitely at the same elevation.
The installation by Clean Solar seemed pretty straight forward to me. They just mounted the Powerwall inside the garage, elevated about 3ft above the floor. That's why I'm just baffled at why Tesla isn't capable of doing the same thing.