Problem when passing value to resolution (Export TIFF)

I´m passing by a strange script behaviour. I´m trying to refine a script to export artboards as TIFF.

So suppose I started "var op = new ExportOptionsTIFF()"

And I set op.resolution = 250

Now I try to run this script via Extended Script Toolkit. I press play and it goes right...But If I make more tests I have this problem:

If I set a differnt resolution (for example, 365) the Script will ignore this new and will use the only value 250 defined in the past (in my first test). If, for a third time, I set another new value, the Extended Script will ignore this value and use the 365 I set in a previous test.

Look´s it´s recording the differnt values I put but it is always delayed one or two times :/

Do not know if I was able to better explain the problem.

Have you already passed by it?? Should I consider this as a problem? Or it´s only an Extendes Script software mistake?

Thank you a lot

Gustavo.