vertical centering of text in tbl rows

[Y T]

GROFF VERSION: 1.20.1 (also with 1.18.1.1)

MACHINE: Linux

OS: Centos 5.3

COMPILER: gcc

INPUT FILES:

----- file1 ------
.LP
.TS
tab(;);
l l.
_
FOO;22
_
.TE
----- end of file1 ----

----- file2 -----
.ps 12
.vs 14
.rs
.sp 1i
.po 1i
.vs 14
.nr 3g \n(.v
.vs \n(.vu-\n(.sp
\l'1i\(ul'
.vs \n(3gu
GOO
.vs \n(.vu-\n(.sp
\l'1i\(ul'
----- end of file2 ----

COMMAND LINE:

groff -t -ms file1
groff file2

DESCRIPTION OF INCORRECT BEHAVIOUR:

With file1, the text is not vertically centered between
the two lines. Specifically, the distance between the
top of the text and the top line is much smaller than
between the bottom of the text and the bottom line.
Using old AT&T tbl/troff, the text is properly vertically centented.

file2 is provided as a possible hint for solving the problem.
This file is a simplified version of the output from
old AT&T tbl.  With groff, this has the same vertical
centering problem as with file 1.  With old AT&T troff,
the text is properly vertically centered.
                                          
_________________________________________________________________
Hotmail: Trusted email with Microsoft’s powerful SPAM protection.
http://clk.atdmt.com/GBL/go/196390706/direct/01/