hope it helps ... i also tried this simple : all the above the same but

"c1":="r1";

"c2":="r1"+2;

"c1":="r1";

still the first c1 is different than the second ....

ok i found you error:

if you check some of your real variables have just 2 byte of space... 

MD18 and MD20 for example

So you have to relocate them, leaving 4 Bytes of space:

MD16 and MD 20 for example... 

You MUST NOT use for other variables the space between them...

Use it:

"x0"  ---> MD0

y0 ---> MD4

r1 ---> MD8

r2 ---> MD12

 r3 ---> MD16

c1 ---> MD20

c2 ---> MD24

s1 ---> MW28

DONT USE Mx1, Mx2, Mx3..... because if you add just 1 bite in them, the result will change... a real number use 4 bytes.

Explanation of byte use:

if you use MD18 and MD20, the byte use will be like this:

for MD18: Use M18, M19, M20, M21

for MD20: Use M20, M21, M22, M23

Data form MD20 will be added to MD18 in bytes M20 and M21

If i declare MD18 = 13 and the MD20 = 15, MD20 will stand with the number, but MD18 will change to a number different of 13

See the image bellow, i declarate a MD24 and a MD26, that happend in the memory of the PLC, both variables take part of 2 same bytes (M26 and M27)

PD: sorry for my english xD