QP.GetPageText(3) works much better, why?

Let's see one PDF file, I uploaded it here:

http://depositfiles.com/files/3945338


Let's select the 3rd page and call GetPageText twice.

GetPageText(0) returns an empty string, but GetPageText(3) works much better, it returns:

"TimesNewRoman",#000000,12.00,46.7520,755.6305,46.7520,773.9953,33.4680,773.9953,33.4680,755.6305,"3/4 "
"Century",#000000,10.50,545.6880,56.6906,545.6880,59.6096,533.0775,59.6096,533.0775,56.6906," "
"DEDPCC+Arial",#000000,12.00,72.4920,73.9706,72.4920,77.3066,59.1000,77.3066,59.1000,73.9706," "
"DEDPCC+Arial",#000000,12.00,90.4920,61.9706,90.4920,532.1882,77.1000,532.1882,77.1000,61.9706,"4. Correction for speaker loudness to maximum sometimes when turning on the power.   "
"DEDPCC+Arial",#000000,12.00,108.4920,73.9106,108.4920,77.2466,95.1000,77.2466,95.1000,73.9106," "
"DEDPCC+Arial",#000000,12.00,126.4920,61.9706,126.4920,514.2554,113.1000,514.2554,113.1000,61.9706,"5. Correction for even if the SIG-Center value of 7009 is edited in the service menu,   "
"DEDPCC+Arial",#000000,12.00,144.4920,67.9706,144.4920,354.2066,131.1000,354.2066,131.1000,67.9706,"  the set value is not reflected when powered on next. "
"DEDPCC+Arial",#000000,12.00,162.4920,73.9106,162.4920,123.4754,149.1000,123.4754,149.1000,73.9106,"  "
"DEDPCC+Arial",#000000,12.00,180.4920,61.9706,180.4920,65.3066,167.1000,65.3066,167.1000,61.9706," "
"DEDPCC+Arial",#000000,12.00,198.4920,56.6906,198.4920,99.3782,185.1000,99.3782,185.1000,56.6906,"<Note> "
"DEDPCC+Arial",#000000,12.00,216.4920,56.6906,216.4920,620.6726,203.1000,620.6726,203.1000,56.6906,"In this particular model, PW IC features CPU function so only PW software update is needed and enough. "
"DEDPCC+Arial",#000000,12.00,234.4920,56.6906,234.4920,761.6174,221.1000,761.6174,221.1000,56.6906,"The user setting will be getting back to shipping condition by software update, however the Lamp timer and adjusted data won’t be "
"DEDPCC+Arial",#000000,12.00,252.4920,56.6906,252.4920,118.1258,239.1000,118.1258,239.1000,56.6906,"changed.  "
"DEDPCC+Arial",#000000,12.00,270.4920,56.6906,270.4920,60.0266,257.1000,60.0266,257.1000,56.6906," "
"DEDPCC+Arial",#000000,12.00,288.4920,56.6906,288.4920,175.9286,275.1000,175.9286,275.1000,56.6906,"<Supplemental Note> "
"DEDPCC+Arial",#000000,12.00,306.4920,56.6906,306.4920,554.5022,293.1000,554.5022,293.1000,56.6906,"  The software is posted on the service department web site and will be available for 6 months. "
"DEDPCC+Arial",#000000,12.00,324.4920,56.6906,324.4920,60.0266,311.1000,60.0266,311.1000,56.6906," "

Why GetPageText(0) gives not good results?

Many thanks in advance.

Thank you, Ingo (our pdf expert).

I have a PDF file, and GetPageText(3) returns an empty string, but GetPageText(4) extacts the text from that PDF. Is the 4th parameter better than the 3rd parameter?

Is there a guarantee method of a text extraction?
As I understand, GetPageText(0) isn't recommended.

Edited by PGU_78 - 07 Mar 08 at 4:08AM