Updated!
It looks like you actually have 7 TPE banked, not 3. Your last update added 23 TPE and spent only 15, but the banked 8 TPE wasn't added to your roster page, which had 1 banked. This update, you added 8 TPE and spent 10 (STR 81 -> 82), spending 2 of your 9 banked TPE. Your roster page now shows the remaining 7 TPE, which you can spend in any future update.
It looks like you actually have 7 TPE banked, not 3. Your last update added 23 TPE and spent only 15, but the banked 8 TPE wasn't added to your roster page, which had 1 banked. This update, you added 8 TPE and spent 10 (STR 81 -> 82), spending 2 of your 9 banked TPE. Your roster page now shows the remaining 7 TPE, which you can spend in any future update.