update error relating to commerce discount [#2787461]

Updating a site with drush to the latest release results in an error seen before.

Performed update: commerce_discount_update_7110 [ok]
exception 'DatabaseSchemaObjectExistsException' with message 'Table field_data_discount_usage_per_person already exists.' in /public/includes/database/schema.inc:660

The table in question is empty in the db; I have removed it, but upon updating it will create that table again, and with it the error message. I believe its the install_helper that may try to create the db table twice (?).

relevant stack trace:
#0 /Users/me/development/the_site/public/includes/database/database.inc(2720): DatabaseSchema->createTable('field_data_disc...', Array)
#1 /Users/me/development/the_site/public/modules/field/modules/field_sql_storage/field_sql_storage.module(269): db_create_table('field_data_disc...', Array)
#2 [internal function]: field_sql_storage_field_storage_create_field(Array)
#3 /Users/me/development/the_site/public/includes/module.inc(922): call_user_func_array('field_sql_stora...', Array)
#4 /Users/me/development/the_site/public/modules/field/field.crud.inc(180): module_invoke('field_sql_stora...', 'field_storage_c...', Array)
#5 /Users/me/development/the_site/public/profiles/commerce_kickstart/modules/contrib/commerce_discount/commerce_discount.install(335): field_create_field(Array)
#6 /Users/me/development/the_site/public/profiles/commerce_kickstart/modules/contrib/commerce_discount/commerce_discount.module(242):commerce_discount_install_helper()
#7 [internal function]: commerce_discount_flush_caches()
#8 /Users/me/development/the_site/public/includes/module.inc(951): call_user_func_array('commerce_discou...', Array)
#9 /Users/me/development/the_site/public/includes/common.inc(7626): module_invoke_all('flush_caches')
#10 phar:///usr/local/bin/drush/commands/core/drupal/cache.inc(99): drupal_flush_all_caches()
#11 phar:///usr/local/bin/drush/includes/drush.inc(724): drush_cache_clear_both()
#12 phar:///usr/local/bin/drush/includes/drush.inc(711): drush_call_user_func_array('drush_cache_cle...', Array)
#13 phar:///usr/local/bin/drush/commands/core/cache.drush.inc(144): drush_op('drush_cache_cle...')
#14 [internal function]: drush_cache_command_clear('all')
#15 phar:///usr/local/bin/drush/includes/command.inc(366): call_user_func_array('drush_cache_com...', Array)
#16 phar:///usr/local/bin/drush/includes/command.inc(217): _drush_invoke_hooks(Array, Array)
#17 [internal function]: drush_command('all')
#18 phar:///usr/local/bin/drush/includes/command.inc(185): call_user_func_array('drush_command', Array)
#19 phar:///usr/local/bin/drush/lib/Drush/Boot/BaseBoot.php(67): drush_dispatch(Array)
#20 phar:///usr/local/bin/drush/includes/preflight.inc(66): Drush\Boot\BaseBoot->bootstrap_and_dispatch()
#21 phar:///usr/local/bin/drush/includes/startup.inc(321): drush_main()
#22 phar:///usr/local/bin/drush/drush(114): drush_startup(Array)
#23 /usr/local/bin/drush(10): require('phar:///usr/loc...')
#24 {main}