HP 15C conditional does not behave as expected

[Siegfried]

Using the below code with the following parameters:

1900 in register 3
-31.24 in register 2
8600 in x

the value in x before the conditional test X>Y? (f TEST 7) is 894.4946 and the value in y is 1.

The test should therefore test positive and the GTO .0 should be executed.
It isn't however.

Any hints what I am missing / doing wrong would be appreciated. I have verified that Y=1 using an R/S before the conditional.

P.S.: This is a correction for minimum safe heights for aircraft to account for low temperature taken from the draft of the new PANS-OPS (where a wrong formula has been published for decades). Therefore all altitude related values are in feet but temperatures are C/K.

Code:

HP 15C
parameters:
ISA Deviation STO 2
Temperature Source Elevation STO 3
Height to be corrected in X


LBL A
STO 1        'temporary store height to be corrected in 1
.0019812        'L0
STO 0        'goes to 0
288.15        'T0
STO .0        'goes to .0
CLx            clear Height correction (Hac) for initial calculation
LBL .0        
ENTER        'duplicate height correction
1            'add 1
+
X<>Y        'move last height correction +1 to Y
RCL +1        'add MDH to H_ac on stack
RCL *0            'multiply by L0
RCL 3          'recall Elev
RCL *0         'multiply by L0
RCL +.0        'add T0
/
1
+
LN
RCL 2           'Delta Tstd    
CHS            '-Delta Tstd
RCL /0          'divided by L0
*
X>Y?               'if new correction is more than previous + 1
GTO .0        'repeat calculation with new correction value
R/S            'if not, stop and show correction'