This is making my head spin but not because of the english but because I´m generally not the brightest bulb in the shop. 
(it would confuse me in german, too)
But I think it could mean that you have to write into the field the amount that was paid in cash and NOT add both amounts together.
I spent another 10 minutes reading all other fields and it seems that I have to send 150 as the total amount and 50 as the previous payments.
I’m confused, but I’m constantly confused by this job, so it doesn’t count.
That´s the way I read it too.
Liked those posts because Tuna Sandwiches.
Okay. Firstly, whoever wrote that documentation needs a bang on the tunahead. And they probably should’ve given an example if it’s that complicated.
I read that as anything in that box is a part payment. So basically a record of anything paid so far.
It’s this bit that confuses me. I guess it’s for the amount due, whether that’s a partial payment (if part of it has already been paid) or a full payment (if it’s all being paid in one go when they check out). So I guess it’s the amount due so far regardless.
So how I interpret it:
Scenario: customer owes 50 for food, and 100 for the room. He wants to pay the 50 in cash and leave the 100 charged to the room.
First field (any previous amounts): 50 (already paid in cash at the restaurant).
Second field (amount due): 100.
I can’t be completely sure about that since it’s so ambiguous. As Milan kind of said, it’s not your English language skills that are the problem – more the explanatory skills of that manual writer 
Hope you get it sorted!
We decided to let the customer tell us whether it’s correct 
I’ll know in… about one month, probably
Yeah, it is not the words I have my problems but the way they are used. I absolutly know what it would mean in german and am still not sure.
However that is a hundred percent the way such documents are worded in german, usually(isn´t that right @someone?). So if I did I direct translation of that it would look like many other cheques, tax papers, letters from the bank etc etc.
How is said this action in english? Passing the buck? 
In the area under “Do not write in this space”, he wrote “Okay”
I would consult the guy who wrote that documentation. Or in other words: Can’t you call the support of the other system or at least a user of that other system? Isn’t there a test interface?
Yes. 
(Plus: developers tend to write shitty, crappy and horrible documentation - especially when it comes to interfaces. I know what I’m talking about.)
…when the documentation even exists!
That is the “shitty” part. 
In French, capot (pronounced KAPO) means “hood” (of a car), capote (pronounced kapot) means condom…
The Dutch word “kapot” on the other hand means broken/kaputt.
Ok, back to the start.
latin Caput - capitis, the head
from Protoitalic *kaput (1) in turn from Protoindoeuropean *káput (2).
Hence to capsize, capoter, cappottare, and probably Dutch kapot too: to dramatically end head down.
(1): de Vaan, Michiel (2008) Etymological Dictionary of Latin and the Other Italic Languages. Leiden: Brill, p. 91.
(2): Mallory, J. P. & Adams, Douglas Q. (2006) The Oxford introduction to Proto-Indo-European and the Proto-Indo-European world. Oxford: Oxford University Press, 176.
The German “kaputt” has its origins in the Frensh capot, but not in the word itself - it’s derived from a card play quotation (faire capot, être capot).
Oh, as in Kate Cupsize Capsize!
Bray is balken and we also have briesen. Is snicker really something any more commonly said of horses than its more direct translation giechelen?
Btw, here are some horse sound words from the best Dutch thesaurus (the second best probably being the Groot Synoniemen Woordenboek by Van Dale).
To illustrate why I think the other one is not as good…
I’d count briesen as one of the snorting sounds (you know, the lip-flapping thing that horses do after the whinnying)
That first one is indeed an interesting book there!
Sound of a rhino! 
