In all the three scenarios the access time consumed is the duration for which the guest user has logged.
show radius [guest-users|server]
show radius guest-users {brief|<GUEST-USER-NAME>}
      show radius server
show radius guest-users {brief|<GUEST-USER-NAME>}
      | radius guest-users {brief|<GUEST-USER-NAME>} | Displays RADIUS server‘s guest user‘s access details: total time for which the
                user has logged in, and the amount of access time remaining. 
 Use this command in the captive-portal context to view time and data statistics for guest user(s) having bandwidth-based or time-based vouchers configured. In such a scenario, the system displays the following information: data configured, data remaining, configured and current bandwidths (for both downlink and uplink), time configured, and time remaining. If bandwidth-based voucher is not applicable to a guest user, the data configured and data remaining values are displayed as ‘unlimited‘. The bandwidth columns are blank. If time-based voucher is not applicable to a guest user, the only value displayed is the time remaining (which is the time till the expiration of the guest user‘s account). Note: For
                  more information on configuring bandwidth-based and time-based vouchers, see user (radius user policy config mode). | 
show radius server
| radius server | Displays RADIUS server related statistical data | 
nx9500-6C8809#show radius guest-users
         TIME (min:sec)
       USED    REMAINING   GUEST USER
       0:00         9:00   time9
       0:00         5:00   time5
       0:00        15:00   time15
       0:00    305416:35   notime
       2:31         7:29   time10
nx9500-6C8809#
      The following example shows a RADIUS user pool with guest users having bandwidth-based, time-based, bandwidth and time based, and no bandwidth or time based vouchers:
nx9500-6C8809(config-captive-portal-wdws)#show context radius-user-pool-policy wdws user time_and_data password 0 both group wdws guest expiry-time 12:00 expiry-date 12/31/2015 access-duration 8000 data-limit 500 committed-downlink 3000 committed-uplink 2000 reduced-downlink 1000 reduce4 user neither password 0 nine group wdws guest expiry-time 12:00 expiry-date 12/31/2015 user data_only password 0 data group wdws guest expiry-time 12:00 expiry-date 12/31/2015 data-limit 125 committed-downlink 1000 committed-uplink 800 reduced-downlink 500 reduced-uplink 400 nx9500-6C8809(config-captive-portal-wdws)#
The following example shows the captive portal access details for the above mentioned RADIUS user pool users:
nx9500-6C8809(config-captive-portal-wdws)#show radius guest-users 
                      TIME (DD:HH:MM:SS)            DATA (kilobytes)                BANDWIDTH (kbps) 
GUEST USER          CONFIGURED     REMAINING    CONFIGURED    REMAINING    CFGD DN  CURR DN  CFGD UP  CURR UP
time_and_data       5:13:20:00    5:12:00:50        512000       433727       3000        0     2000        0
neither            till expiry  221:19:44:54     unlimited    unlimited
data_only          till expiry  221:19:44:54        128000       127587       1000        0      800        0
time_only           3:11:20:00    3:11:19:47     unlimited    unlimited
Current time: 17:15:07
nx9500-6C8809(config-captive-portal-wdws)#