[Orgmode] Time computation errors

[Francesco Pizzolante]

Hi,

Going on in discovering org-mode, I found 2 problems when trying
to make computations on times.

Consider the following example:

--8<---------------cut here---------------start------------->8---
* Test
#+COLUMNS: %25ITEM(Description)  %Time1{:} %Time2{:} %Time3{:}

#+BEGIN: columnview :hlines 1 :id local
| Description | Time1 | Time2 | Time3  |
|-------------+-------+-------+--------|
| * Test      |  3:30 |  3:00 | #ERROR |
| *** Item 1  | -1:30 |  1:00 | #ERROR |
| *** Item 2  |  4:00 |  2:00 | #ERROR |
#+TBLFM: $4=$2+$3
#+END:

*** Item 1
    :PROPERTIES:
    :Time1:    -1:30
    :Time2:    1:00
    :END:

*** Item 2
    :PROPERTIES:
    :Time1:    4:00
    :Time2:    2:00
    :END:
--8<---------------cut here---------------end--------------->8---


Problems:

1) The sum of Time1 for Test headline is wrong: 3:30 instead of
   2:30;

2) I'm unable to sum times through a formula (see Time3 column).
   The same formula works perfectly when you replace times with
   integers.

Any feedback is welcome.

Thanks,
Francesco