Shell Programming and Scripting

IFS="'"
CONFIGURATION_ARRAY=( '-N 0 -m 0' '-N 0 -m 1'  )
for configuration in ${CONFIGURATION_ARRAY[@]}
do

//DEBUG
N=${configuration%-*} //-N 0
M=-${configuration##*-} //-m 0
a="-N 0"
b="-m 0"
printf "%s \n" $N //-N 0
printf "%s \n" $a //-m 0
if [ $N == $a ]
then
           echo "SAME" //it's not the same - WHY???
fi

if [ $M == $b ]
then
           echo "SAME" //it's the same
fi

sudo  ./MY_PROGRAM $configuration //I want this to work but: doesn't work
sudo  ./MY_PROGRAM $N $M //doesn't work
sudo  ./MY_PROGRAM $N //doesn't work
sudo  ./MY_PROGRAM $M //works!!! 
sudo  ./MY_PROGRAM $a $b //works!!! but a and b contain the same strings as N and M do.. what the hell?

echo $configuration

-N 0 -m 0

./MY_PROGRAM $configuration

TEST="-N0 -m 0"

./MY_PROGRAM $TEST

./script "-N 0 -m 0"

./script "-N" "0" "-m" "0"

CONFIGURATION_ARRAY=( '-N 0 -m 0' '-N 0 -m 1'  )

for configuration in "${CONFIGURATION_ARRAY[@]}"
do
        printf "Quoted does not split: %s\n" "$configuration"
        printf "Unquoted split:  %s\n" $configuration
done

Quoted does not split: -N 0 -m 0
Unquoted split:  -N
Unquoted split:  0
Unquoted split:  -m
Unquoted split:  0
Quoted does not split: -N 0 -m 1
Unquoted split:  -N
Unquoted split:  0
Unquoted split:  -m
Unquoted split:  1