Consistent behavior, adequate appearance
IMO you need to clarify (for us, or maybe for yourself) what needs to be consistent, and what not.
Consistent behavior means: Things that look the same should behave the same.
Adequate appearance means: the look helps the user predict the functionality.
With these ad-hoc definitions by humble me, they are not antagonists.
I've seen many attempts at consistent appearance for things that are functionally different. Now, with some age, I consider that a mistake in many cases - at least, when the similar looks were motivated by similar or shared implementation.
IMHO, striving for a similar look between 150 forms (OMG!) isn't even a good goal. How are your users to tell what they are just doing?
Can you spot the difference? Very consistent, but a recipe for disaster.
In this example, details like selecting the receiver, selecting products and amounts etc. should behave the same - that's consistency. Appearance, OTOH should be significantly different.
In practice, I see two possible problems:
Developer preferences: A "one size fits all" approach goes down easier with developers. Instead of implementing 150 forms, they implement a form generation engine that mostly configures itself from database meta data. (We just like to solve meta problems, and hate repetetive work. This even is the more efficient approach if the result is what the user needs.)
User perception: Replacing an existing UX is different from introducing a new one. For non-technical users, the Forms are the application - they don't know business logic and backends, they just know lists and fields and buttons.
This means if you change the UI completely, you may see a lot of friction when the solution is rolled out, simply because the users see a unfamiliar application, while IT thinks it's the same data, so only little training is required.
Which takes me to the part of my reply that I loathe to say: Be careful with what you throw out. An efficient and elegant UI may be much more error prone than a ugly but familiar one.
 As Michael Zuschlag points out, don't worry to much just be prepared for the rollout.