Synthesis error - RAM resource ?

In stratix 4, there are 3 type of memory blocks - MLAB, M9K and M144K. Each one can hold 640, 9216 and 147456 bits respectively. There are different n words x word width configurations. For example, the M9k can be used as a 8k x 1bit, 4kx 2bit, 2k x 4bit, 1kx8 or 9bit (the 9th bit is meant for parity, but can be used for data), 512x16 or 18bit or 256 x 32 or 36 bit (4 parity bits). Because these are the only configurations, if you had a a 13 bit word, you would have to have it configured as 512x16, and you would not be able to use the last 3 + 2 parity bits (unless you had some parrallel data that could fit in there). This would mean you're wasting memory.