Time entering and calculated totals

if you have excel 365 you can add this as a Lambda function (either using Excel Labs or directly in the Name Manager):

ttime=lambda(in, if(AND(isnumber(in),IFERROR(in<1,0)),in, let(
         inTemp, SUBSTITUTE(in,"m",""),
         intime, IFERROR(--inTemp,--left(inTemp,len(inTemp)-1)),
             pm,0.5*(upper(right(inTemp,1))="P") ,
            out, if(len(intime)>2,(left(intime,len(intime)-2)+ right(intime,2)/60)/24,intime/24)+pm,
         out)));

then by calling =ttime(A1) it will convert what it sees in A1 to time based on:
a) it is already excel recognized time input
b) it is 1-4 digits followed by "a", "p", "am", or "pm" (actually it only cares that there is only 1 non-"m" character and if that 1 non-"m" character is a "p" it is afternoon)
c) if it is only a number (e.g. 1015 or 2100) it will assume it is also a time
any other format or combinations of formats will probably result in errors or bad time values. Hope it is helpful