Two files encrypted with related data versus one file

I have some code that takes a list of credit-card numbers, splits the number into two chunks, one chunk is 8 characters long, the other chunk is the remainder.

Each series of chunks is saved into individual files, for example my test data looks like (these are test CC numbers):

378282246310005
4111111111111111
4242424242424242
378734493671000
4242424242424242


So, file X would contain:

37828224
41111111
42424242
37873449
42424242


and file Y would contain:

6310005
11111111
42424242
3671000
42424242


Each record is separated by a common delimiter (a newline character).

File X is saved to a TrueCrypt volume using AES, and file Y is saved to a different TrueCrypt volume, also using AES, but using a completely unrelated key.

My question is, does doing this lower cryptographic strength due to this structure?

The reason why I bring this up is that if you know the contents of one file, you can make assertions about the contents of the second, due to credit-card numbers adhering to LUHN-10 (mod10) specifications.

For example, if I know file X's contents, I know the corresponding record in file Y must pass the LUHN-10 check, and therefore knowing file X exposes information about file Y, Y's potential value is reduced by a factor of 10.

Slightly off-topic, but does storing a single file with full credit card numbers separated by a common delimiter expose information, if the attacker knows the structure of the file?

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