pls help me regarding-Coriolis flowmeter/Flow element

Dear Sir's

I have recieved a Coriolis flowmeter/Flow element (Mass Flowmeter) and our order specifications are mentioned below :

process data

Fluid- Liquid , Flow normal - 418 GPM , Flow max -460 GPM, Operating pressure-590psig ,Max pressure -1100psig , Operating temp-105 deg f, max temp-150 degF, Operating Density -.5 ,Molecular mass - 48.14,Operating viscosity- .1, Max allowable pressure drop - 10 psig

SENSOR UNIT

Type- coriolis , Function -massflow , Connection flange size -6" 600lbs, Facing -RF ,Body-304ss ,Sensor housing -SS,Enclousre-IP65, Max range-0.0GPM ,Min range -1000GPM ,ACCURACY - +-0.2% flow rate

My doubt is that Received sensor unit is having connection flange 4x3"(Reducing) 600lbs (outer flange is 4") where as our order specification was only 6" 600lbs

When we contacted vendor they confirmed that sensor flange they calculated through pressure drop and it is ok for this application

Plz tell me is it ok or not?How can we confirm whether that vendor is saying ok or not

Thanks

ronie