how cobertura destroy m2 build low formula coverage

i'm perplexing configure fight digest build destroy line bend coverage next given thresholds. i've controlling settlement presumption page 455 glorious book , nonetheless success. here's applicable dash project's maven 2 pom:

<build>
...
<plugins>
  <plugin>
    <groupid>org.codehaus.mojo</groupid>
    <artifactid>cobertura-maven-plugin</artifactid>
    <version>2.2</version>
    <configuration>
      <check>
        <!-- per-class thresholds -->
        <linerate>80</linerate>
        <branchrate>80</branchrate>
        <!-- project-wide thresholds -->
        <totallinerate>90</totallinerate>
        <totalbranchrate>90</totalbranchrate>
      </check>
      <executions>
        <execution>
          <goals>
            <goal>clean</goal>
            <goal>check</goal>
          </goals>
        </execution>
        <execution>
          <id>coverage-tests</id>
          <!-- "verify" apportionment occurs only before "install" -->
          <phase>verify</phase>
          <goals>
            <goal>clean</goal>
            <goal>check</goal>
          </goals>
        </execution>
      </executions>
      <instrumentation>
        <excludes>
      <exclude>au/**/*constants.*</exclude>
        </excludes>
        <ignores>
      <ignore>au/**/*constants.*</ignore>
        </ignores>
      </instrumentation>
    </configuration>
  </plugin>
  ...
</plugins>
...
</build>

as i say, coverage news works fine, problem "install" idea isn't unwell should line bend coverage next specified thresholds. does anyone have working, so, does your pom feeling chronicle cobertura maven using? i'm controlling maven 2.0.9 cobertura 2.2.

i've attempted googling reading cobertura docs, nonetheless fitness (the latter small contend least).