| Variable | KPSS test value* | 1% critical value | 5% critical value | 10% critical value | Test results |
| Overcharges | 0.246 | 0.216 | 0.146 | 0.119 | Smooth |
| Overspend | 0.500 | 0.216 | 0.146 | 0.119 | Smooth |