def mapRanges(povpct, povlow, povhigh, paylow, payhigh):     # 135, (133..150), (3.0..4.0)
    """
    Evenly map povpct in [povlow..povhigh] to [paylow..payhigh].
    All aruments and return value are scaled percentages (*100).
    See # comments to the right for an example's expected calcs.
    This scheme may or may not match the final IRS technique.
    """
    povrange = povhigh - povlow                              # 17  = 150 - 133
    payrange = payhigh - paylow                              # 1.0 = 4.0 - 3.0
    povincr  = povpct  - povlow                              # 2   = 135 - 133
    pctincr  = povincr / povrange                            # pct = 2 / 17
    paypct   = paylow + (pctincr * payrange)                 # 3.0 + (pct * 1.0)
    return round(paypct, 2)                                  # per IRS: round to nearest 100th