Question: Units conversion problem

This is an addition to the following post:

http://www.mapleprimes.com/questions/141795-Unit-Conversion-Problem

But I use the clickable facilities of Maple.  Here is the problem:

>32[[degC]];

                         32[[degC]]
right-click -> Units -> Replace units -> degF

                         288           
                         --- [[degF]]
                          5            

>evalf[5]( (2) );
                       57.600[[degF]]

but if I do that:

>convert(32, 'temperature', 'degC', 'degF');

                              448
                              ---
                               5
                           
>evalf[5]( (4) );
                             89.600

Why the conversion is bad when you try to do it by the clickable way????????????

--------------------------------------
Mario Lemelin

Maple 18 Ubuntu 13.10 - 64 bits
Maple 18 Win 7 -  64 bits
messagerie : mario.lemelin@cgocable.ca
téléphone :  (819) 376-0987