This is probably the limitation of the smartness of the importdata() function.
If you look at filec.textdata, you will get a clue. It tries to separate the data based on 'line-10'. 'line-10' is read in correctly. All the lines below, either the digit "0" or "0." are treated and included in as the text data.
So for 'line-20', "0" is truncated but ".5474641" is still read in as "0.5474641"
for "line-30', "0." is truncated thus "59778373" is read in as "59778373"
For your input file text format, it's better to use textscan(), although it can't be done with one line of code.
For this particular file "'tem-009.out'", I tried A=readmatrix(filename,'filetype','text') and it does give correct result.