I try to calculate the correction of cold temperature for altimeter , i use for this the equation 24 of the Engineering Sciences Data Unit (ESDU) publication but it give me very high number . if i take for example the given conditions altitude of aircraft 1000 ft 0 ft for aerodrome altitude t0 288 K temperature deviation from the ISA = 259.9812 L0 = 0.001981 the result is 599777.4389 ft is too big , the expected result is 60 ft So where is mistakes ?

I try to calculate the correction of cold temperature for altimeter , i use for this the equation 24 of the Engineering Sciences Data Unit (ESDU) publication but it give me very high number . if i take for example the given conditions altitude of aircraft 1000 ft 0 ft for aerodrome altitude t0 288 K temperature deviation from the ISA = 259.9812 L0 = 0.001981 the result is 599777.4389 ft is too big , the expected result is 60 ft So where is mistakes ?

EDIT : So i corrected the ISA dev according to what Ralph said but the result still incorrect i joint the step of calculation : the expected result is 60 ft