Hi Derfred,
The N1 was over 5% lower at the lower OAT.
Please see Page 31 of section 71-00-00
http://www.air.flyingway.com/books/e...aintenance.pdf
You should see there is about 5% N1 difference for the engine giving the same thrust operating at temperatures 30 degrees apart.
When using ATM calculations, for approximately every 30 degrees C (i.e. 10% change in air density) difference between assumed temperature and actual OAT, then the actual Accelerate Stop Distance will be reduce by approximately 10% of the assumed ASD.