Extending tier 2 general visa while on Maternity leave

I’m currently on Tier 2 General Visa valid until June 2016. I will be looking to extend my Visa around April 2016, I will continue to be with my current employer and under the same SOC code. I will be in Maternity leave in April 2016 though. As I will be in Maternity leave, my salary requirements will be less than the required minimum, I believe this is acceptable. However,

1. Should my salary before I start maternity leave in December 2015 be meeting the ‘experienced rate’ salary requirement as per the SOC code?
2. If so, my current basic salary is below the ‘experienced rate’ salary requirement as per the SOC code, but I do get on-call/stand-by allowances which when considered meets the salary requirements of my SOC code. Are on-call/stand-by allowances considered when calculating the salary requirements?