CW 6933 2115+ 01/03/2013; Mostly groups of five letters w/ a distinct "++" then "NNGTN" repeated five times at one point, still in progress @2121; "+ + + IWNDA DWNDA DVNDA DWNDA DLNDA" @2123; Ended w/ a "+ + T" @2135
Note: Having fun with a just installed MultiPSK.
This does indeed sound like cut numbers, and might well be Cuban M08a.
One thing to remember when using software to decode CW is that no software is infallible, and the lower the signal to noise ratio the more errors even good software will make.
Your “+” signs are probably actually Morse code digraphs AR, the + sign and the digraph AR use the same dits and dahs, but AR is generally the translation in this application. + is seldom used in CW, while AR is a frequent shorthand for stop copy or all received. Writing it as + is not wrong at all, but can be confusing to some. Also, if you were to look for a description of M08a it would define this as AR, not +, and might mislead someone who does not know they are the same character.
Other errors in the example you have posted. These cut numbers use the pattern ANDUWRIGMT = 1 to 0, example is A=1, N-2, D=3, U=4, etc to T=0. As you see from that there are no L or V, but your copy shows each used, this is most likely an error on the part of the software. Possibly a dit or dah from the character before or after was incorrectly parsed to that character.
With software decoders and signals without large signal to noise you can often record a few minute segment of CW and play it back repeatedly, getting slight variations in the transcribed code each time. The higher the signal to noise ratio the better the transcription is likely to be.
I try to tell people who do not copy code by ear that software decoders are a nice tool that can give you a general idea of what is being sent, but treat it like something you read on the Internet, it might not all be there, and sometimes it is an out and out lie.
T!