The way I interpret the Oct Marathon promo, there isn't anything wrong with the promotion period from 1st to 31st Oct -
1. Clause 2b - you can register for the promo between 1st and 31st Oct (both dates inclusive). Some register on 31st Oct and it is shown that the registration was successful
2. Clause 2c - you must deposit fresh funds into yr registered account such that the deposit balance on 31st Oct is at least $100,000 higher than deposit balance on 30th Sep. You can always deposit between 1st Oct and 30th Oct and register on 31st Oct and you will still be eligible for the BI for month of Oct. If you have deposited early, you will qualify this clause
3. Clause 10 would have warned participants not to make last minute deposits - "For avoidance of doubt. any deposit , withdrawal or otherwise transaction in relation ....... the last day of the calendar month falling on either a Sunday, public holiday or a bank holiday will not be taken into consideration for the purpose of computation of BI" .... Oct 31 Diwali holiday is one such day