Omnidyne

I didn't receive wages at the same time. I ended my job in early August and only started my next job in September. Should the tax codes not add up to 12,570? At the moment my personal allowance only adds up to 10,911 (853L from old job, 237TX from new job) , even though I've paid all the tax I need to through PAYE, with no overlalp

I've only ever had income from employment, and as such, pay all my taxes through PAYE through my employer. I had and have non cash benefits. I've recently switched jobs, and for some reason my total personal allowance for the year has gone from £12,570 to £10,911 (even including my previous job's Tax code), my tax account is saying I've underpaid tax by £170 (gross £1,659), which can't be true. Anybody know if switching jobs somehow reduces the personal allowance?